Grand Seiko made a big splash at last year’s Watches & Wonders with the launch of the Kodo Constant-Force Tourbillon, the brand’s first complicated mechanical wristwatch. For 2023, the brand is back with another first-time complication that will likely be one of the most talked-about watches of the show, the Grand Seiko Tentagraph SLGC001.

The first purely mechanical Grand Seiko chronograph ever, the Tentagraph is a high-spec sports chronograph that fills a hole in the Grand Seiko portfolio. “Tentagraph” is a portmanteau of the four key features of the watch: TEN beats per second, Three-day power reserve, Automatic winding, and of course, the chronoGRAPH.

Initial thoughts

The Tentagraph is an important watch for Grand Seiko that enables the brand to stand toe to toe with Rolex, Omega, Zenith, Breitling, and other stalwarts in the popular category of mechanical sports chronograph. Not only is the category a hitherto untapped commercial opportunity for Grand Seiko, it is an opportunity for the brand to demonstrate its technical know-how and ambition.

In this context, I would have expected the brand to release an integrated chronograph movement, perhaps based on the 6S movement family. But Grand Seiko has chosen to build a modular chronograph calibre based on the 9SA5, the flagship Grand Seiko automatic movement introduced in 2020, signalling the brand’s commitment to the calibre and its proprietary Dual Impulse Escapement.

My colleague Richard Lee notes that the 9SA5 is an odd choice of base for a chronograph. This is because the movement’s fourth wheel is in the centre of the movement, being intended for central seconds. This design necessitates the use of an indirect train to reposition the running seconds to the three o’clock sub-dial. This extra train, combined with the friction inherent to all vertical clutch chronograph movements, reduces the power reserve by 10% compared with the time-only 9SA5.

And then there’s the price. While Grand Seiko has built its reputation by offering strong value-for-money, its prices have inched up in recent years. The Tentagraph continues this trend with a retail price of US$13,700. This is about US$1,100 less than the current retail price of the Rolex Daytona, and US$2,700 more than the Zenith Chronomaster Sport. While it is still something of a value proposition, it is modest one and arguably less compelling in terms of value than past Grand Seiko models.

Evolution 9 style

It may seem hard to believe, given Seiko’s illustrious history with chronographs dating back to 1969, that there has never been a mechanical Grand Seiko chronograph. While Grand Seiko has produced Spring Drive-powered chronographs for several years, and Seiko has produced mechanical chronographs for both its Seiko and Credor brands, the launch of the Tentagraph marks the first time that a mechanical chronograph will bear the Grand Seiko brand.

Unsurprisingly, the Tentagraph is designed according to Grand Seiko’s Evolution 9 design language, the default style for the brand’s flagship models.

The Tentagraph features a dark blue dial decorated with Grand Seiko’s signature “Mount Iwate” texture. Named after the mountain near Grand Seiko’s workshop, the grained, radial texture has been in use since 2006, and with good reason. It’s unique enough to be distinctly Grand Seiko, but subtle enough to work in a variety of watches. It’s a smart, if conservative, choice for a milestone watch. 

The case and bracelet are made from the brand’s proprietary “high-intensity” titanium, which Grand Seiko claims is both lighter and more scratch-resistant than stainless steel. As has become the norm for sport chronographs, the bezel is ceramic.

Lightweight titanium is a good choice for the Tentagraph because it is a large watch, measuring 43.2 mm in diameter and 15.3 mm thick. For context, that’s 0.4 mm thicker than Omega’s Speedmaster Super Racing, widely criticised for its thickness, and 1.7 mm thicker than the Zenith Chronomaster Sport.

Understanding the 9SC5

To understand the 9SC5, we need to reflect on the launch of the 9SA5 in 2020, which ushered in a new era for Grand Seiko on several fronts. Not only was the 9SA5 the first Grand Seiko movement to feature a free-sprung balance and overcoil hairspring – hallmarks of higher-end luxury watches – but it also debuted the brand’s own proprietary Dual Impulse Escapement which offers improved efficiency compared to the ubiquitous lever escapement. Grand Seiko describes the 9SA5 as the best mechanical movement it’s ever created, and I agree.

The 9SA5 also introduced a new, more attractive style of finishing for the brand’s mechanical movements. While earlier generation calibers like the 9S85 are decorated selectively on just the visible components, the 9SA5 offers more thorough Swiss-style decorative finishing, with non-visible surfaces decorated as well.

Building on this platform is the 9SC5 in the Tentagraph. On paper, the 9SC5 has all the bells and whistles one would expect from a modern chronograph movement at this price point, namely a column wheel, vertical clutch, and three-day power reserve. 

But in terms of construction, Grand Seiko has taken a different approach from that of establishment Swiss brands like Rolex, Omega, and Zenith. The 9SC5 features a modular construction, marrying the 9SA5 base caliber to a new, dial-side chronograph module.

While the layout of the chronograph registers and date window are identical to that of the Seiko NE88, the brand notes that the chronograph module in the 9SC5 is exclusive to Grand Seiko. 

This modular construction results in a thick movement, adding 2.8 mm in height and 1.4 mm in diameter to the base 9SA5 movement. At 8 mm thick, the 9SC5 is 0.4 mm thicker than Omega’s portly cal. 9900. For additional context, the Rolex cal. 4130 and Zenith El Primero 3600 in the Chronomaster Sport are 6.5 mm and 6.6 mm thick respectively. 

That said, the movement is an intriguing entrant into the sport chronograph segment given its novel escapement, 5 Hz frequency, and the precision that Grand Seiko is known for.

Speaking of precision, Grand Seiko has extended its already rigorous 17-day testing protocol for this new complication, adding three extra days to validate the performance while the chronograph is running and ensure compliance with the Grand Seiko standard of +5 to -3 seconds per day.

Key facts and price

Grand Seiko Evolution 9 Collection Tentagraph
Ref. SLGC001

Diameter: 43.2 mm
Height: 15.3 mm
Material: Titanium
Crystal: Sapphire
Water resistance: 100 m

Movement: 9SC5
Functions: Hours, minutes, running seconds, chronograph, and date
Winding: Automatic
Frequency: 36,000 beats per hour (5 Hz)
Power reserve: 72 hours

Strap: Titanium bracelet

Limited edition: No
Availability: From June 2023 at Grand Seiko boutiques and select retail partners
Price: US$13,700

For more, visit grand-seiko.com

Grand Seiko has just opened the first of its own boutiques in Asia outside of Japan, which is located at the Marina Bay Sands casino resort in Singapore. Situated along a corridor alongside major luxury watch brands, the store reflects Grand Seiko’s ambitions in positioning itself alongside establishment brands.

The inaugural store run by Grand Seiko’s recently-established Asian arm, it becomes the new platform for enthusiasts to experience the brand’s timepieces, including its top-of-the-line complications. It’s the first milestone for Grand Seiko Asia-Pacific, the joint venture set up last year with its longtime retailer in the region, Thong Sia Watch Co. Ltd. 

Akio Naito, Chairman of Grand Seiko Asia-Pacific and President of the Seiko Watch Corporation, explained the choice of the city state for its first boutique in the region: “Singapore is home to some of the most knowledgeable and passionate luxury watch enthusiasts in the world, and we are excited to provide them with a more direct interaction with the brand…”

Keeping in line with the brand’s philosophy, “The Nature of Time”, the boutique’s interior is modern while sticking to traditional materials and details. The store sports a clean, modern design with warm wood for the floor and cabinets, retaining the subtle, Japanese refinement that the brand is known for. 

The boutique is also the place for clients and enthusiasts to learn more about the brand. In particular, it allows them to experience up-close some of the rare timepieces in the brand’s lineup, including the Kodo Constant-Force Tourbillon SLGT003 that was awarded the Chronometry Prize at last year’s Grand Prix d’Horlogerie de Genève (GPHG).

The Kodo Constant-Force Tourbillon SLGT003.

The Grand Seiko boutique is located at the Marina Bay Sands and is open daily from 10:30 am-10:00 pm:

#B2M-35 The Shoppes at Marina Bay Sands
2 Bayfront Avenue
Singapore 018792

For more, visit grand-seiko.com.

Correction March 1, 2023: The Singapore store is the first Grand Seiko boutique in Asia outside of Japan that is run by Grand Seiko itself. Prior boutiques are operated by third-party retailers or distributors.

Twenty twenty-three is the 110th anniversary of the first-ever Seiko wristwatch, an occasion that has resulted in series of limited editions, starting Presage SBP359 and continuing with Prospex SPB333 “White Birch”. Now the anniversary edition goes upscale with Grand Seiko.

The brand has debuted a remake of the first Grand Seiko, the ref. 3180 nicknamed “First”, but with a twist. The Grand Seiko Watchmaking 110th Anniversary Limited Edition SBGW295 takes after the vintage original in terms of design, but does so with a titanium case and striking dial finished in black urushi with gold-powder markings.

Initial thoughts

Grand Seiko has done several reissues of the “First”, most of which look virtually the same. So yet another limited-edition remake of the 3180 would certainly be much less compelling. The SBGW295, however, is notably different, in a good way.

At first glance, it’s apparent that the dial of the SBGW295 is special. Urushi has a deep, glossy finish that will contrast perfectly with the markings in sprinkled gold powder, also known as maki-e. Add to that the titanium case and the result is a handsome watch with a high-contrast aesthetic that is atypical of Grand Seiko.

But the SBGW295 does cost US$13,800, which is expensive for a time-only watch of this quality and specification, as well as being pricey relative to Grand Seiko’s own offerings. It costs 50% more than the equivalent titanium model of the most recent “First” remake, albeit one without a lacquer dial. The dial admittedly is more artisanal than usual, so perhaps the price can be forgiven, especially since it is a limited edition.

Urushi lacquer and maki-e

To create this illustrious dial, Grand Seiko turned to traditional Japanese arts.

First was urushi, lacquer obtained from the sap of the Japanese lacquer tree. Urushi has been used for centuries in Japan to create beautiful and intricate works of art. Here the lacquer gets its high gloss, jet black finish from the addition of iron powder

To complement and contrast the urushi base, the brand tapped Isshu Tamura, an artisan who specialises in maki-e, a traditional lacquer technique that relies on sprinkled powder and flakes to create a decorative pattern. This dial features 24k gold powder applied by hand to form the hour markers and logo.

Aside from the dial’s unique colour scheme, the rest of the SBGW295 retains the dimensions of previous anniversary models. The retro case measures 38 mm in diameter and 10.9 mm in height.

Most notably, it is in “brilliant hard titanium”, an alloy developed by Seiko that is lighter than the grade 5 titanium used for most timepieces. At the same time, it is much harder than stainless steel, boosting its scratch resistance.

And to go with the titanium case is a strap designed specifically for this model. It’s made of narrow fabric and leather strips that have been woven with a technique traditionally utilised to make parts of samurai armour.

Like earlier iterations of the 3180 remake, the SBGW295 is powered by the cal. 9S64. Since its launch almost a decade ago, the calibre has served as the mainstay for its dress timepieces.

It sports a respectable power reserve of 72 hours and an excellent daily rate of +5 to -3 seconds per day according to Grand Seiko testing standards.

Key facts and price

Grand Seiko Watchmaking 110th Anniversary Limited Edition
Ref. SBGW295

Diameter: 38 mm
Height: 10.9 mm
Material: Brilliant hard titanium
Crystal: Sapphire
Water resistance: 20 m

Movement: 9S64
Features: Hours, minutes, seconds
Frequency: 28,800 beats per hour (4 Hz)
Winding: Hand wind
Power reserve: 72 hours

Strap: Fabric strap or leather strap

Limited edition: 500 pieces
Availability: Starting February 2023 at Seiko boutiques and retailers
Price: US$13,800

For more, visit grand-seiko.com.

When Grand Seiko (GS) made its return in 1998, the inaugural SBGR001 model was powered by the 9S55, the first modern-day GS calibre. Now the brand is marking the 25th anniversary of the 9S movement family with a pair of limited editions. The Heritage Collection Caliber 9S 25th Anniversary Hi-Beat 36000 SBGH311 and the Heritage Collection Caliber 9S 25th Anniversary SBGR325.

The Hi-Beat SBGH311 has a patterned dial, while the more affordable SBGR325 has a dial with a brushed finish. Both are modelled on the original model of 1998 and sport the same 37 mm case.

SBGH311 (left) and SBGR325

Initial thoughts

With their 37 mm cases and clean styling, the new 9S pair hark back to the GS watches made from the late 1990s to mid 2000s. That is unsurprising since they are meant to commemorate the first model with the 9S movement, which made its debut in 1998. The Hi-Beat SBGH311 does have a fancier pattern dial, but one that is relatively subtle in its shades-of-grey texture. As a result, they will appeal to anyone who wants a smaller, simpler GS watch.

Another upside of the relatively simpler execution are the prices, which place the pair amongst the most affordable self-winding GS watches. The SBGH311 is US$6,600 and the SBGR325 about 20% less.

SBGR325

Old-school size

The SBGH311 has a textured dial in silvery grey inspired by clouds that’s matched with a blued-steel seconds hand. And the “GS” emblem is gilded in a nod to the fact that this is an anniversary edition. Notably, the steel case is only 37 mm in diameter, making it one of the most compact men’s GS models in the current catalogue.

SBGH311

Inside is the 9S85, one of GS’s Hi-Beat calibres. That means it runs at 36,000 beats per hour (5 Hz), while having a 55-hour power reserve.

The movement is identical to the standard version, except for the spiral-form rotor in titanium with a “anodic oxidation” treatment – basically a chemical process that creates a pale-blue oxide layer on the rotor surface – that’s also been used in past GS anniversary models.

9S85

Sized exactly the same is the SBGR325, which is simpler in both mechanics and dial finish, while also being more affordable. The case is steel while the dial has a pale blue metallic finish with radial brushing, with colour provided by the blued-steel seconds hand and gilded, applied “GS” logo.

SBGR325

About as no-frills as it gets for a current GS, the SBGR325 is powered by the 9S65 movement that runs at 28,800 beats per hour (4 Hz), allowing it a 72-hour power reserve. Like its Hi-Beat counterpart, the 9S65 in the SBGR325 has a titanium rotor that’s been chemically treated to give it a dark blue oxide finish.

9S65

Key facts and price

Grand Seiko Heritage Collection Caliber 9S 25th Anniversary
Ref. SBGH311 (Hi-Beat 36000)
Ref. SBGR325

Diameter: 37 mm
Height: 13.3 mm
Material: Stainless steel
Crystal: Sapphire
Water resistance: 100 m

Movement: 9S85 in SBGH311; 9S65 in SBGR325
Features: Hours, minutes, and seconds
Frequency: 36,000 beats per hour for 9S85; 28,800 beats per hour for 9S65
Winding: Automatic
Power reserve: 55 hours for 9S85; 72 hours for 9S65

Strap: Steel bracelet

Limited edition: 1,200 pieces each
Availability:
SBGH311 – Starting January at Grand Seiko online boutique, followed by physical boutiques and retailers in February
SBGR325 – From April 2023 at boutiques and retailers
Price:
SBGH311 – US$6,600
SBGR325 – US$5,300

For more, visit grand-seiko.com.

On very rare occasions does Grand Seiko create unique versions of its watches. But it has done so with a unique version of the Kodo Constant-Force Tourbillon – the one-off reference SLGT001 – that will go under the hammer at Phillips’ New York auction December 11, with some proceeds from the sale going to a children’s charity.

Anyone who read our earlier in-depth, two-part story on the Kodo (part I covers the watch and part II its technical features) will understand the the impressive technical achievement that is its movement. The SLGT001 has all of that, but in a unique execution specifically for the auction.

Engraved “Unique Piece No. 1/1” on the back, the SLGT001 is instantly recognisable as a one-off.

While the standard version of the model has a monochromatic grey palette, the SLGT001 is set apart by its colour: heat-blued and gilded components against rhodium-plated bridges. Most of the screws are blued steel, while the three-armed tourbillon carriage is blued titanium.

And the SLGT001 is also distinguished by its case material. Unlike the standard model that has a case made up of both titanium and platinum, this is entirely in Brilliant Hard Titanium, the brand’s proprietary alloy that boasts a brighter, more silvery hue than most titanium alloys.

A portion of the proceeds from the sale of the SLGT001 will go to the Children’s Heart Foundation. Besides benefiting a good cause, the winning bidder will also get a trip to Japan to meet the team behind the SLGT001 at the Grand Seiko workshop in Shizukuishi, a town in northern Japan.

The SLGT001 is lot 100 in the sale; for more visit Phillips.com.

Having launched several elegant and concise time-only watches this year, Grand Seiko has unveiled something once again simple but still unusual: the first regular-production, manual-wind Spring Drive 44GS, the Heritage Collection SBGY011 “Asaborake”.

The SBGY011 combines two of the best elements of Grand Seiko (GS), namely the hybrid Spring Drive movement and the distinctive 44GS case. While the combination has been seen before, the SBGY011 brings something new to the table because the movement is manual wind, instead of self-winding as most Spring Drive calibres are.

Initial thoughts

I appreciate the SBGY011 because it retains the key features of the original, namely the 44GS case, silver dial, and hand-wind movement – but reinterpreted to incorporate contemporary elements such as the Spring Drive movement and patterned dial.

Combined with the 44GS case, the silver dial gives the SBGY011 an aesthetic that’s close to the vintage 44GS of 1967. In fact, it’s essentially a modern, more technically-capable version of the original, which also contained a hand-wind mechanical movement.

In fact, the SBGY011 is only the second hand-wind Spring Drive watch with a 44GS case, and the first and only one that’s not a limited edition.

The hand-wind movement matters because the 44GS case is exponentially more attractive when it’s thin; in this case it is only 10.5 mm high. In comparison, a typical automatic Spring Drive is around 13 mm thick.

Notably, despite being a regular production model, the SBGY011 has a textured dial, something typically reserved for limited editions. The texture is finely patterned and not as pronounced as on other GS models.

While purists might prefer a simpler dial with a brushed finish, the dial of the SBGY011 has a subtle texture that’s almost indiscernible at arm’s length, so the watch should appeal to a variety of enthusiasts.

The dial texture is especially subtle in silver

Hand-wind Spring Drive

Made of repeating criss-crossed lines, the dial pattern is a familiar one, having been applied in various colours across different models. But GS patterned dials are usually colourful, which makes the present example stand out.

At 40 mm in diameter and just over 10 mm high, the case is more compact than the average modern 44GS, but retains the signature sloping mirror-polished flanks that define the design.

Over on the back, the view is more typical GS. Inside is the cal. 9R31 that debuted in 2019 but used sparingly since. It’s a practical calibre with twin barrels that provide a power reserve of 72 hours, which can be read off the back of the watch via a tiny power reserve indicator near the barrel.

The cal. 9R31 is derived from the cal. 9R02 found in the top-of-the-line GS models, but simplified in terms of technology, construction, and finish – explaining the affordability of the SBGY011 (the watches with the 9R02 cost almost ten times as much).

Key facts and price

Grand Seiko Heritage Collection SBGY011 “Asaborake”
Ref. SBGY011G

Diameter: 40 mm
Height: 10.5 mm
Material: Stainless steel
Crystal: Sapphire
Water resistance: 100 m

Movement: 9R31
Features: Hours, minutes, and seconds
Frequency: Spring Drive
Winding: Manual
Power reserve: 72 hours

Strap: Crocodile leather with folding clasp

Availability: Starting December 2022 at Grand Seiko boutiques and retailers
Price: US$8,100

For more, visit grand-seiko.com.

Correction November 16, 2022: The 9R31 movement was used not only in limited edition models but also the SBGY007 launched in 2021.

Having delved into the origins, concept, and design of the Grand Seiko Kodo Constant-Force Tourbillon SLGT003, we now turn to the granularity of its technical qualities. The Kodo is first and foremost a chronometer in the vein of the watches that lay behind the founding of Grand Seiko (GS).

A brand focused on precision timekeeping since its establishment in 1960, the opening act of GS in its first decade was competing in observatory chronometer trials at Neuchatel and Geneva – and winning, much to the horror of the Swiss. Several decades later the brand is still pursuing perfect accuracy in both mechanical, quartz, and hybrid formats, most notably with the novel Spring Drive.

The Kodo powered by the cal. 9ST1 is the latest, and arguably greatest, endeavour in chronometric precision from GS. But it is like no GS that has come before it. Rather than rely on modern technology and materials, the Kodo instead revisits traditional mechanical solutions, namely as the constant-force mechanism and tourbillon. Combining the two in a wristwatch mark a milestone for GS, or any Japanese watchmaker for that matter.

To understand the mechanical systems within the Kodo, we must first understand the fundamental challenges in precision timekeeping. The factors that influence precision fall into two categories, the first related to the barrel or energy supply, and the second, gravity’s effect on the balance or oscillator.

Energy challenges

The barrel is the source of energy in a conventional mechanical movement. It’s essentially a cylinder that houses the mainspring, which is a coiled length of metal that stores energy when wound up tightly. While it is an effective energy source, the mainspring nevertheless has a weakness: it delivers steadily declining torque as it winds down and the coils of the spring slacken.

The lower torque means a less energy for the oscillator, resulting in a shorter swing of the balance, more precisely described as a drop in amplitude. With a shorter distance travelled, the time needed for the balance to complete an oscillation diminishes, so the movement will beat faster or at a higher frequency.

That said, readers who have come across the term isochronism – the property of maintaining the same frequency despite changing amplitude – might wonder why it doesn’t apply here. While an ordinary balance largely operates according to this phenomenon, it does not do so perfectly because of inconsistencies in material and fabrication.

That is why watches can keep relatively good time with diminishing torque, varying only seconds each day for instance, but never perfectly. Modern materials science and manufacturing technology does help with maintain isochronism, but such innovations are invisible to the observer.

Traditional solutions of the sort that watch enthusiasts revere focus instead on addressing the root cause of the problem, which is the variation in torque of the mainspring. This approach certainly requires mechanical intervention, which is where constant-force mechanisms come in.

There are two types of constant-force mechanism. The first works directly with the power supply, like a fusee and chain, stack freed, or simply a stop-work, while the second sits along the going train, such as a remontoir. The former evens out the torque delivered by the barrel regardless of the mainspring’s state of wind, while the latter relies on a buffer spring to store and deliver small, even portions of energy to the balance at fixed intervals.

An example from Swiss watchmaking that incorporates both types of constant force mechanisms, a chain and fusee as well as a remontoir, the Ferdinand Berthoud FB 2RE

While the chain and fusee is magnificent, it is bulky and inevitably occupies half the movement. In fact, it takes up so much space that it only made it into a wristwatch about three decades ago.

In contrast, the remontoir is a more elegant solution that’s compact and more effective. Controlling the power flow right before the balance ensures all errors that occur along the gear train are dealt with, which is why the late George Daniels described it as “by far the best method of smoothing the power supply” in his treatise Watchmaking.

Unsurprisingly given GS’s penchant for refined engineering, the Kodo is equipped with a remontoir, specifically one that’s integrated into the tourbillon regulator, an unorthodox construction that we explained below.

The twin mainsprings of the Kodo are visible below the sub-dial for the time – together they provide more stable torque than a single barrel, though not with the exactitude of a chain and fusee

Newton’s Law

The second primary source of errors in a mechanical movement is gravity as it interferes with the oscillation of a balance depending to a degree that depends on the position of the watch. This exacerbates the inherent imperfections of a balance assembly that arise from manufacturing or assembly oversights.

As we have already discussed this topic at at-length, we will skip the problems and instead cover only the solutions. One of the best-known is the centuries-old trick of constantly changing the position of the balance average out such errors, otherwise known as the tourbillon.

The Kodo incorporates not one but two systems to tackle inaccuracy, a remontoir inside a tourbillon. Both sit on the same axis with power flowing from the mainspring to the remontoir and then the tourbillon.

One of the twin barrels inside the Kodo. Image – Grand Seiko

The Kodo is equipped with twin barrels that operate in parallel, meaning both unwind simultaneously. This set-up typically delivers more energy per period of time than a single mainspring.

According to Mr Kawauchiya, double barrels set up in parallel typically have shorter running times than the twin barrels arranged in series. But the twin barrels in the cal. 9ST1, he adds, are notable for offering a relatively long running time of 72 hours.

As an aside, why do the best modern chronometers from the likes of Grand Seiko and Omega keep excellent time without any fancy, traditional mechanisms? The Grand Seiko Standard that entry-level mechanical GS watches has to meet is within +5.0/-3.0 seconds a day – and these are watches with no compilations that cost under US$10,000.

Keeping good time affordably, the 9S63 movement found in GS models priced around US$7,500

One reason is that the movements are simple and only require relatively low tolerance in fabrication and assembly, which allows for more efficient production while maintaining quality.

Another factor is the science of modelling and manufacturing has improved enough that impressive accuracy is possible with a standard Swiss-lever construction.

Finally, such everyday watches are typically automatic, allowing the mainspring to remain almost fully wound at all times, eliminating the decline in torque seen in a manual-wind watch that’s only wound every day or two.

Still, anachronistic technology makes for an impressive object, which is exactly what the Kodo is.

One of the rare few

While tourbillon wristwatches are now common, few are equipped with a constant-force mechanism and even fewer have both a tourbillon and constant-force mechanism.

Arguably the most famous example equipped with both is the F.P. Journe Tourbillon Remontoir d’Egalite. Mr Journe’s concise invention utilises a thin blade spring to store and release energy to the tourbillon cage every second.

But there are also other interpretations of the concept that are more elaborate and perhaps more elegant, most notably integrating the remontoir into the tourbillon. Past examples include the magnificent Double-Wheel Remontoir Tourbillon pocket watch made by Derek Pratt in 1997, which has not one but two remontoir escapements in the tourbillon. More recently, and more usual coming from a mainstream brand, is the IWC Portugieser Sidérale Scafusia that combines a constant-force tourbillon with a variety of astronomical complications.

Finally there’s the Andreas Strehler Trans-Axial Tourbillon that most closely resembles the Kodo in its approach. Both rely on a remontoir that’s not only within the tourbillon cage, but also shares the axis of the tourbillon, resulting in an impressive construction that’s vertically symmetrical.

The F.P. Journe remontoir with its thin blade spring

The twin escape wheels and remontoir of the Derek Pratt pocket watch, which uses spiral remontoir spring instead of linear blade spring as found in the F.P. Journe. Image – Timothy Treffry

Why Kodo

The watches mentioned above show that there are precedents to the Kodo, albeit very, very few. From a historical perspective, the Kodo might not be as significant as the Derek Pratt pocket watch – yet since GS is still establishing itself as a serious maker of complications – but its fundamentals are truly excellent.

From the perspective of the brand itself, the Kodo is a milestone for GS and indeed historically significant for the brand. It boasts multiple firsts for GS: tourbillon, constant-force escapement, as well as open-worked movement. But the Kodo is not just regurgitating ideas from the past. Instead it Kodo manages to distinguish itself thanks to several innovations not found in other watches.

The first innovation are the nested, double carriages, one each for the tourbillon and remontoir. Innermost is the tourbillon cage, which is conventional in function and rotates in tiny steps as expected, eight steps a second to be precise.

But the remontoir cage is unusual. It encloses the tourbillon cage and advances once every second, so it doubles up as a deadbeat seconds indicator. But it is definitely more impressive visually than a seconds hand because the entire three-armed cage springs forward each second accompanied by the confident tick of the remontoir wheel.

An extremely complex construction with a triple three-arm set up (for a total of nine arms): the outermost trio forms the three-armed bridge, and the innermost set of arms is the tourbillon cage, while the remontoir cage is sandwiched between the two

The second innovation is actually hinted at by its name, 鼓動 or kodo, which is “heartbeat” in Japanese. As with all remontoirs, the remontoir in the Kodo creates a ticking sound similar to the tick-tock of an escapement when it releases every second.

But the cal. 9ST1 actually emits two perfectly synchronised pulses at a steady pace – these arise from the remontoir and escapement respectively – creating a rhythmic beat. The fact that the escapement beats at the relatively high frequency of 4 Hz is even more impressive, since most tourbillon movements run at a lower frequency to minimise energy consumption.

Synchronising the beats might seem like a simple task but it is a bona fide feat of micro-engineering since any inconsistency in the frequency will result in the rhythm slightly, but noticeably, out of sync. The perfect rhythm demonstrates one of the Kodo’s strength, an ultra-precise construction made possible by parts fabricated with cutting-edge technology such as ultraviolet lithography (UV-LIGA).

The high level of technology used in manufacturing the movement parts set the Kodo apart from comparably complicated timepieces that are often made the traditional way – and this is a good thing, especially when considering the subsequently artisanal decoration of the cal. 9ST1.

“I realised in the early prototype stage that it was not easy to make the escapement and remontoir tick together in an exact 16th note rhythm,” explains Takuma Kawauchiya, the designer of cal. 9ST1, “Slight eccentricities of the gears and their axes, or clearances between the axis and jewel holes would cause the constant force, which should rotate once for every eight times the escapements vibrates, to instead rotate once every seven or nine times instead, making it difficult to hear a clean 16th beat.”

The solution, says Mr Kawauchiya, is a stopper as well as extremely precise tolerances. “The stopper slides over the small teeth of the stop wheel eight times, and to ensure that the stop wheel and stopper disengage exactly on the eighth time required strict tolerances for the parts would not be required in the mass production of normal movements.”

Putting it together, however, is a painstaking process. “During final assembly, the movement is placed in a quiet room with no one else present and I listen to the ticking for one minute,” says Mr Kawauchiya, “If there is even one inaccurate beat, the stopper position is adjusted slightly, and I continue listening until a clean 16th beat is achieved.”

“Rotating the stopper is a painstaking process that can damage the parts of the carriage, but the joy of overcoming this risk and achieving a beautiful 16th note is exceptional,” adds Mr Kawauchiya with pride.

The balance wheel of the Kodo. Image – Grand Seiko

Two halves

Mechanical complexity aside, the Kodo has a beautifully symmetrical movement, as is often the case for tourbillon movements with a constant force mechanism.

The cal. 9ST1 is divided into two halves with the vertical line of symmetry running straight through the dial at 12 o’clock and the constant-force tourbillon at six o’clock. Each half houses a barrel, with each barrel accompanied by a different but visually comparable set of gears, namely planetary gears for the power reserve mechanism on the left, and intermediate wheels for time setting on the right. 

According to Mr Kawauchiya, the symmetrical arrangement of the wheel train layout was, unsurprisingly, a deliberate choice of the development team from the start. But the positions of the gears serve another purpose.

“We also wanted to balance the appearance of the complex, multi-layered structure of the constant-force tourbillon carriage… by giving a multi-layered structure to the barrel as well,” explains Mr Kawauchiya, “After much consideration of what to layer, we came to the conclusion that it would be a planetary train for the power reserve mechanism and the intermediate wheels for time setting.”

“For me, a three-dimensional effect of a movement is one of the major attractions of mechanical watches and I believe looking at a pocket watch is one of those joys. However, it is quite a difficult task to create the three-dimensional looks of a pocket watch in a wristwatch,” says Mr Kawauchiya.

“In order to achieve this, we created height differences between the gears in the power reserve train… while the gears have chamfered spokes and teeth to prevent them from looking thin and monotonous, and even the MEMS gears [made via LIGA] have minute steps in the spokes to create a three-dimensional effect,” He continues, “That kept the overall thickness of the movement as thin as possible, while creating as much of a three-dimensional effect as possible within that limited thickness.”

Overview of the constant-force tourbillon

The cal. 9ST1 of the Kodo is certainly an impressive and complicated construction, and one with few peers. But each it operates on the traditional principles, so it is most easily understood one section at a time.

The fundamentals of the cal. 9ST1 are similar to that of a standard movement, which means it has barrels, gear train, and escapement. The major differences between the cal. 9ST1 and an ordinary movement lie at the end of the gear train, or more precisely at the fourth (or last) wheel that typically drives a seconds hand. Instead of a fourth wheel, the cal. 9ST1 has a remontoir wheel.

Power flows from the barrels through the gear train to the remontoir wheel, which is where it gets interesting. The remontoir acts like a typical fourth wheel, meaning the remontoir wheel makes a full revolution every minute. But unlike a conventional fourth wheel that moves forward in an almost-smooth motion, the remontoir wheel advances one step every second. As a result, it is actually a double-function complication.

The Kodo logically makes use of that. A three-armed remontoir bridge is fixed on the top of the remontoir wheel, allowing it to act as jumping seconds indicator, with the ruby mounted on one of the arms serving as the pointer. It’s worth mentioning that the wheel and bridge forms the entirety of a remontoir cage. In a typical tourbillon watch, the gear train drives the tourbillon cage, but here it drives the remontoir cage.

Since the remontoir cage sits where the tourbillon cage would normally be, the tourbillon has to fit within the remontoir cage. Remember also that the remontoir drives the tourbillon within it, but to understand the connection between the two, we have to start with how the remontoir works.

The key to the constant-force ability of a remontoir is the spiral buffer spring known as the remontoir spring. Essentially a tiny, secondary mainspring, the remontoir spring winds down quickly and as it does so propels the parts sitting above it.

Logically, the tourbillon cage sits directly above the remontoir spring. Each unwinding of the remontoir spring discharges a constant amount of energy, such that the tourbillon is driven by a consistent dose of power each second, thus making it a constant-force tourbillon. And because the remontoir spring is directly under the tourbillon cage – both rotate on the same axis – it is also a co-axial, constant-force tourbillon.

The tourbillon cage (red) is nested within the remontoir cage (blue)

How it really works

The basics of the cal. 9ST1 are clear: the gear train ends with the remontoir, and the remontoir in turn drives the tourbillon. But it is a complicated and delicate system with much mechanical ingenuity to appreciate.

The fundamental element of the assembly is the tourbillon. Remember that it is a mechanism designed to complete one revolution every minute, during which the escape wheel, pallet fork, as well as the balance wheel are rotating along with the cage. This constantly changes the position of the balance wheel, thus averaging out errors induced by gravity.

The Kodo, however, adds a remontoir into the mix. Here tthe remontoir is locked in a feedback loop with the tourbillon. The remontoir spring, and hence the remontoir cage, releases in one-second steps in a process that’s regulated by the tourbillon. In other words, though the tourbillon is driven by the remontoir, it conversely controls the periodic release of the remontoir.

Both the tourbillon and remontoir are co-axial, a set up that eliminates the need for an intermediate wheel in between, which reduces power loss through friction.

The remontoir spring unwinds at a controlled rate that is dependent on the escapement within the tourbillon. If the escapement were absent, then the remontoir will release instantaneously instead of once every second.

The operation of the remontoir lies in the fact that it’s essentially a miniature mainspring with enough energy to drive the tourbillon for about one second. And that’s exactly why the remontoir is a constant-force mechanism – the spring delivers the same, small dose of energy to the escapement within the tourbillon, so collectively the remontoir and escapement form the constant-force tourbillon system.

Now that we understand how remontoir spring powers the tourbillon, it’s time to look at how the spring is recharged. Attached to the base of the tourbillon cage is a C-shaped steel ring with a protruding arm, which rotates along with the tourbillon cage.

At the end of the protruding arm is a synthetic ruby shaped like a pallet jewel. Next to it is a five-spoked, white ceramic wheel that is blocked by the pallet jewel of the arm. Together, they form a secondary escapement with the jewel acting as a blocking mechanism for the remontoir.

As the C-shaped ring rotates along with the tourbillon cage, the tip of the jewel slides past one tooth of the ceramic wheel, releasing the remontoir spring, allowing the remontoir cage to rotate forward one step, until the next tooth of the ceramic wheel contacts the pallet jewel. This takes place at one0second intervals – in other words, the remontoir is released after the tourbillon cage advances six degrees clockwise, which is eight “ticks” of the 4 Hz escapement.

As mentioned earlier, since the remontoir cage is constructed to recharge every second, its motion allows it to function as a jumping seconds indicator. This double function is common for such remontoir mechanisms, but the Kodo executes the idea in a unique manner as the remontoir cage is co-axial with the tourbillon cage.

Other interesting features

While the constant-force mechanism and tourbillon are the heading features of the Kodo’s cal. 9ST1, it actually incorporates several interesting – and practical – features.

One is the hacking function of the tourbillon that’s constructed in an unusual way. A conventional tourbillon-hacking mechanism – a rare complication for a tourbillon – typically relies on a flexible stop lever that contacts the balance wheel and halts everything instantaneously.

But the Kodo has the hacking lever contacting the lower ring of the tourbillon cage, which allows the balance wheel within the cage to oscillate for a few more cycles before it eventually stops.

On its face, this method is not the most impressive from a visual perspective since the tourbillon does not stop instantaneously. However, stopping the carriage is an uncommon approach because of its complexity; stopping the cage abruptly while allowing the balance to oscillate can potentially damage the escapement.

Implementing this hacking mechanism required finesse in both design and execution. According to Mr Kawauchiya, “The magnitude of the force applied to the carriage during hacking, however, is actually very small because the frictional force required to stop the carriage rotation is calculated and the spring force of the lever is designed to stop the carriage with the minimum necessary safety ratio.”

“Therefore, the force used to hacking the carriage does not damage any components,” he explains, “However, since the spring force of the lever must be strictly controlled, the spring is slightly bent by hand during assembly to fine-tune the spring force… The amount of movement of the spring tip is so tiny that it requires very delicate work.”

“Kodo stops the rotation of the tourbillon carriage by moving the spring tangentially to the carriage, rather than radially – when the spring is disengaged, a slight counterclockwise rotational force is applied to the carriage to ensure the restarting of the tourbillon,” continues Mr awauchiya, “This method is an application of a mechanism that was originally found in calibre 45 and the stopwatch developed by Seiko for the 1964 Tokyo Olympics.”

Another notable feature is the grand sonnerie-style winding click, which is symmetrical just like the twin barrels that flank the click. A classical and elegant approach to the winding click, the grand sonnerie-style winding click is rarely found in modern watchmaking and is being used for the first time by Grand Seiko.

(A detailed explanation of the grand sonnerie-style winding click can be found here.)

The grand sonnerie-style (right), with one of the sharply open-worked barrel ratchet wheels just adjacent

As with all of the Kodo, the grand sonnerie-style winding click was the result of purposeful design. “There are three reasons for adopting the grand sonnerie-style winding click,” explains Mr Kawauchiya, “First, for functional reasons, a winding click that can distribute the force between two click springs is suitable for the high torque of the twin barrels in the Kodo.”

“Secondly, Kodo is all about symmetrical layout of the movement as a whole, and it was ideal for the intermediate wheel connecting the two ratchet wheels to integrate the function of a click,” he continues. “Lastly, as you pointed out, we believe that the grand sonnerie-style winding click is both traditional and very beautiful, and we wanted to try this style, which has never been used by Seiko or Grand Seiko before.”

Also apparent is the fact that the barrels are designed to slip to prevent overwinding, a feature borrowed from automatic movements. This can be deduced visually as there is a lack of a distinct recoil mechanism on the ratchet wheel click – a feature otherwise required to prevent the high torque spike from a fully-wound barrel.

Mr Kawauchiya mentions there is an additional benefit of a slipping mainspring relating to efficiency: “It allows us to design a smaller amount of recoil for the ratchet, which means minimum rotation of the winding stem and crown is needed to activate the winding click, thereby reducing loss of energy due to recoil during winding.”

“Since the movement has two barrels to be wound by hand, we designed it to minimise the loss during winding,” Mr Kawauchiya continues, “At the same time, we wanted to create a pleasant winding sound and clicking feel, so we changed the design of the click found in the T0 [concept movement] to the grande sonnerie-style in the Kodo.”

Accuracy

Since the cal. 9ST1  has not one but two mechanisms for precision timekeeping, it is natural to compare its performance with other GS movements, especially the brand’s historical pinnacle of timekeeping achievement, V.F.A. or “Very Fine Adjusted”.

Vintage V.F.A movements were accurate to within a minute per month, while modern V.F.A. movements are regulated to achieve a maximum daily deviation of +3/-1 seconds. On the other hand, the Kodo accurate to +5/-3 seconds a day. Why the disparity?

I discussed this with GS representatives at W&W. The designers of the cal. 9ST1, including Mr Kawauchiya, explained the rationale with two key reasons.

The first lies with the regulating process behind each type of movement. Regulating a V.F.A. movement and cal. 9ST1 of the Kodo are entirely different processes.

A V.F.A. movement is essentially a top-performing version of a standard calibre like the cal. 9S85, which means it is selected from a large pool of already-regulated standards movements and then further regulated by a specially-trained watchmaker to conform to an even tighter standard.

But the same approach is impossible with the cal. 9ST1, since only two dozen examples of the movement will be made – and that includes prototypes. There are simply not enough of them.

The second, and perhaps more crucial, reason is the length of testing. The mean daily rate of the Kodo is measured twice during during testing, at the 24- and 48-hour marks. In contrast, a V.F.A. movement is tested only after 24 hours of running.

Accuracy is measured over a longer period for the Kodo, which is logical considering the movement incorporates a constant-force mechanism that is meant to optimise timekeeping over prolonged periods. Even though the Kodo is regulated to +5/-3 seconds a day like a standard GS movement, it is more impressive because of the difficulty in achieving the same accuracy over a duration that’s twice as long as the standard testing period.

“Regarding Kodo, our priority is different from that of V.F.A.,” says Keiko Naruse, a senior marketing manager at Seiko Watch Corporation, “Kodo aims to provide the stable accuracy for longer periods thanks to constant force and tourbillon.”

She adds, “Theoretically, a V.F.A.-accurate watch with constant force and tourbillon could be made by following the V.F.A. approach, but when determining the product specifications for Kodo, we prioritised stability over a long period of time in consideration of actual use for the wearer.”

That aside, I believe that it is far more difficult to regulate a movement as complicated as the cal. 9ST1 as compared to an ordinary movement. The extra parts at the end of the gear train in the cal. 9ST1 might, rather counterintuitively, hinder the pursuit better accuracy due to friction, but there’s no question that the cal. 9ST1 has the upper hand over its simpler brethren over longer periods thanks to the remontoir.

Concluding thoughts

Intriguingly, Grand Seiko reports that the Kodo runs within +5/-1 seconds per day in real life testing on a wrist, as opposed to +10/-1 seconds per day for a generic 4 Hz movement (and +8/-1 seconds per day for a generic high-beat, 5 Hz movement.

With that in mind, it is fair to conclude that GS is being extremely conservative in the accuracy promises being made for the Kodo. If I ever lived out a fantasy and had the Kodo on the wrist for a few weeks, I am certain it would keep time much better than the stated rating.

With that mind, it would probably have been more effective to announce a superior timekeeping standard for the Kodo, at least from a marketing perspective. That said, relatively conservative marketing claims are typical of GS’s modest approach despite its very fine products. And who knows, perhaps a more elaborate testing regime is in the pipeline.

Still, leaving aside the numbers, the Kodo is an impressive and highly complex object. It is clear that every single element of the movement as well as the case has been carefully considered and then executed to a high level. Even thought GS has never produced a watch like this before, it has managed to surpass even some of the most experienced competition.

Key facts and price

Grand Seiko Kodo Constant-Force Tourbillon
Ref. SLGT003

Diameter: 43.8 mm
Height: 12.9 mm
Material: 950 platinum and Brilliant Hard Titanium
Crystal: Sapphire
Water resistance: 10 bar

Movement: Cal. 9ST1
Functions: Hours, minutes, dead-beat seconds, tourbillon with constant-force mechanism 
Winding: Manual wind
Frequency: 28,800 vibrations per hour (4 Hz)
Power reserve: 72 hours

Strap: Calfskin strap with platinum folding buckle, and additional double-sided crocodile strap

Limited edition: 20 pieces
Availability: Starting October 2022 from Grand Seiko’s retailers and boutiques
Price: US$350,000; or 40 million Japanese yen before tax

For more, visit grand-seiko.com.

The first complicated mechanical watch from the brand in its six decades years of history, the Grand Seiko Kodo Constant-Force Tourbillon SLGT003 is an impressive example of high horology. The Kodo is self-explanatory: it is equipped with a highly skeletonised and sensitively finished movement boasting a one-second remontoir and tourbillon, both mounted on the same axis.

The Kodo is an interesting watch in all respects, tangible and intangible, making it worth a detailed examination – exactly the focus of this two-part series. In this first instalment, we explain the development and conception of the Kodo, as well as the decoration of its movement. In the second part that will be published subsequently, we detail how the movement works and analyse how it compares to the competition.

A surprise

Evolved from the T0 concept movement unveiled just two years ago, the Kodo is undoubtedly a milestone – and a major step upwards – for the Japanese watchmaker that’s historically been focused on simple but high-quality everyday watches. Like conventional Grand Seiko (GS) watches, the Kodo is all about high-quality timekeeping, but it is far from simple.

An example of a typical Grand Seiko, which is strikingly different from the Kodo, yet not so different in terms of philosophy

Well known for its quest for high precision – amongst its earliest timepieces were observatory-tested chronometers – GS has done much research and development in the cutting-edge timekeeping technologies other than mechanical, including quartz and its proprietary Spring Drive. Now an established brand with strong development and manufacturing capability, GS often utilises modern materials and techniques, such as nickel alloy wheels made via lithography. And the Kodo goes even further, being the first GS to have ceramic wheels.

The Kodo continues that decades-long quest for precision, but is instead rooted in traditional solutions to chronometry. It’s a return to nuanced, mechanical systems rather than high-tech materials such as silicon. This traditional approach makes the Kodo an unexpected creation from a mainstream brand, given such esoteric watches are typically the work of niche or independent watchmakers.

Another highlight of the Kodo are its tangible technical qualities. One obvious highlight is the construction of the constant-force mechanism and tourbillon. The constant-force cage contains the tourbillon cage, but both rotate on the same axis. Already a rare combination of complications, it’s even rarer that the two mechanisms are constructed in a co-axial manner.

Another is the fact that the Kodo is a skeletonised watch, resulting in a movement is practically see-through. While the Kodo is the first-ever skeleton GS, it does build on an in-house expertise as Seiko does offer a variety of hand-made skeleton movements under the Credor label.

Initial thoughts

The result of ten years of development – done entirely in-house without on external specialists – the Kodo represents an impressive culmination of GS’ watchmaking prowess. It is also notable because it’s unusual for a large brand that mostly concentrates on affordable watches to venture out of its comfort zone and invest resources in creating something this exotic.

In typical GS fashion, the Kodo is rigorous in its technical execution and best described as a chronometrically-focused mechanical treat. The tourbillon and remontoir together is a rarity that is historically the preserve of respected independent watchmakers such as F.P. Journe. But the Kodo does one better by integrating the remontoir into the tourbillon with a pair of co-axial cages. While the overall concept is not a historical first, the movement has few peers and certainly ranks amongst the most accomplished.

The design might be controversial because it departs significantly from the familiar GS aesthetic. Admittedly, I didn’t warm to the design when I first saw photos of it, but the hyper-mechanical style makes sense when I examined the watch in the metal. The Kodo has a complex and intricate appearance that is paradoxically visually light; its aggressively mechanical design elements are elegant in their own way.

In the hand, the watch is stunning, both for the incredible detail but also in how the movement components gleam in the light. The reflective and dark movement components were evidently conceived to maximise the interplay of light and shadow, a principle that GS proclaims to utilises across its designs. But whereas that depends on the surfaces of external components like the hands and dial in a typical GS watch, the Kodo transforms the movement into a stage where light and shadow dance.

Priced at US$350,000, the Kodo is the most expensive GS watch ever, far surpassing the brand’s previous record holders that pricey because they were high-jewellery timepieces. But the big number is the natural and reasonable consequence of its mechanical complexity. More pertinently, the price is within the ballpark for comparable watches by both independent and establishment brands.

Importantly, the appeal and value of the Kodo goes beyond its tangible qualities – it is a historically significant watch, being the first of its kind by an Asian watchmaker.

Aesthetics

Though magnificent in technical terms, the Kodo is nevertheless controversial in terms of design, at least in the eyes of traditionalists. That’s because the Kodo is unlike any other GS. Instead it goes all out to showcase its mechanics via a movement that’s entirely open-worked and centred on the large, nested cages of the remontoir and tourbillon. This makes the Kodo both the first GS with a tourbillon as well as the first skeleton.

Admittedly I was a little sceptical when I first saw the stock images of the watch, but I changed my mind as soon as I laid eyes on it during Watches & Wonders (W&W). Characterised by a highly mechanical appearance, the watch is strikingly intricate but avoids being loud or messy. It’s difficult to sum up why exactly the Kodo is attractive, but it is.

Since the people behind the watch were present during the presentation at W&W, I quizzed them about the origins of the design.

It turns out one of the key aspirations behind the Kodo’s aesthetic is familiar, having been applied to more conventional GS watches. That is the contrast between light and shadow, typically exemplified by the multifaceted and impressively finished hour markers and hands found on every GS watch. Found only on the case and dial in ordinary GS timepieces, the interplay between light and shadow has been extended to the movement in the case of the Kodo.

While the use of reflections and light is familiar to GS, the Kodo interprets the concept in a modern manner, albeit in a way that remains Japanese. The brand refers to the design approach as seeking airiness, which is self-explanatory given the see-through nature of the movement.

This was achieved by first open-working the movement components and constructing the calibre in layers, a process that required both the watch designer and movement constructor to work in sync. The result manages to capture the light, shadow, and everything in between, creating a dynamic, nuanced mechanical landscape despite the monochromatic finish.

As the creators of the Kodo explained its origins, it dawned on me that the themes that informed the design of the Kodo are exemplified by a handful of notable details. The first is the monochromatic palettes that’s just shades of grey, which serves to dial down down the visual complexity while giving it a more refined appearance. This is especially obvious when the Kodo is compared against the T0 concept movement that was dressed in blue, gold, and grey.

The next detail concerns the dial for the time that’s made up of a chapter ring carrying hour markers. It creates a focal point for the wearer that lets the rest of the movement recede into the background. Along with the tourbillon at six o’clock, the sub-dial unites the densest sections of the movement, creating a good contrast with the transparent sections below.

Another is the case of the Kodo. Skeletonised just like the movement, the case is a twin-alloy affair made up of a platinum inner case contained within an outer case of Brilliant Hard Titanium. The two-part construction utilises the harder titanium alloy to protect the softer precious metal within (however, the pictured watch is the prototype that has a case entirely in German silver).

The resulting watch looks nothing like a typical GS and is surely polarising. But as was my experience, seeing it in the metal and then coming to understand the rationale behind its development certainly helps to form a positive impression. Despite its unorthodox aesthetics, the Kodo is entirely understandable as a product. Being the first ever highly complicated GS, it has to stand out and it certainly succeeds.

That said, I still look forward to seeing some equally technically complex in a more restrained and classical package, something that is quintessential GS. That would certainly appeal to the purist GS enthusiasts.

From T0 to 9ST1

Unveiled in 2020, the T0 concept movement was the starting point for the cal. 9ST1 in the Kodo. Though the two are similar in construction, they are entirely different movements. Both have different diameters and thickness, with the cal. 9ST1 being smaller and thinner in order to fit inside a wearable wristwatch. To understand how the T0 led to the cal. 9ST1, we spoke with Takuma Kawauchiya, the watchmaker who constructed the Kodo and its movement.

“In developing the 9ST1 from the T0, design changes were made from various perspectives,” says Mr Kawauchiya, “[It went beyond] miniaturisation, and more than 90% of the parts were redesigned.”

The T0 concept movement of 2020. Image – Grand Seiko

“When we decided to commercialise T0, Yu Ishihara, the watch designer, first designed a case for the T0 movement just as it was, and then made a mock-up using a 3D printer to verify the physical design,” continues Mr Kawauchiya.

“As a result, we concluded that the movement needed to be smaller in order to achieve perfect wearability and the ideal degree of freedom in design,” adds Mr Kawauchiya, “Ishihara and I discussed various ways to reduce the size of the T0 without changing its basic layout, and we made major changes mainly in the layout of the power reserve train and the structure of the carriage bridge.”

Despite its complexity, the Kodo is surprisingly thin, a quality that is obvious when observing its profile

Though the overall arrangement of the key parts of the movement remain unchanged from the T0 to the cal. 9ST1, many details were subtly altered as a result of the redesign. Amongst them is the power reserve indicator, which remains in a similar position but with an entirely different orientation.

“For the power reserve train, Ishihara edited the CAD model of the movement and proposed a new approach, something no other designer can do,” says Mr Kawauchiya.

“Based on Ishihara’s suggestion, we made the design into details and added a new bridge with a power reserve indicator, Mr Kawauchiya continues, “As a result, the power reserve indicator was turned inward, reducing the outer diameter of the movement and preventing legibility loss due to the curve of the crystal.”

As for the gigantic carriage at six o’clock, Mr Kawauchiya says, “The carriage arm at six o’clock in particular was an obstacle in reducing the outer diameter of the movement.”

“Ishihara and I considered several patterns in changing the structure of the three arms of the carriage, but we could not find a shape that was more beautiful than the three arms,” he explains, “In the end we decided to keep it as it is and make the movement as small as possible.”

“Since it was difficult to make the carriage smaller than that in the T0, we accomplished this by reducing the thickness of the carriage bridge, downsizing the seconds index, and changing the arm fixing structure,” explains Mr Kawauchiya.

But scaling down the movement was not merely an exercise in reduction. It had to be done while maintaining a high level of shock resistance. “The challenge was to make the parts thinner and smaller while meeting the shock resistance required for Grand Seiko,” says Mr Kawauchiya, “We conducted numerous drop tests to find a structure that was as thin as possible while maintaining strength.”

Mr Kawauchiya is particularly proud of the movement’s robustness, “As a result, Kodo’s diameter was reduced from 36.3 mm of T0 to 35.0 mm, while still passing drop tests and other impact resistance tests.”

Interestingly, Mr Kawauchiya points out the similarity between the cal. 9ST1 and the high-beat cal. 9SA5 that was also unveiled in 2020 to mark the 60th anniversary of Grand Seiko.

“In order to stabilise the accuracy of the balance, we adopted the screwed balance developed for cal. 9SA5,” says Mr Kawauchiya. But the influence of the cal. 9SA5 on the cal. 9ST1 is arguably more obvious in the decorative aspects of the movement.

The 9SA5

Finishing

“Based on our experience with the T0 and cal. 9SA5, we also focused on the following three points for a more pleasing appearance,” says Mr Kawauchiya, referring to the aesthetics of the movement.

“First, the chamfer of the main plate and the bridge is 0.05 mm wider than that of the T0 to give the movement a deeper appearance. Second, nine different types of hole jewels were newly designed to match the 9ST1 movement size, paying attention to the outer diameter, thickness, and even the size of the oil reservoir,” explains Mr Kawauchiya.

“Third, the angle and direction of the grinding wheel were also designed to minimise the steps in order to achieve the most beautiful wave pattern finish [also known as circular Côtes de Genève]. In order to minimise the amount of grinding, the inclination of the movement is adjusted in the order of microns while applying the wave pattern finish.”

All of that incredible attention to detail can only be appreciated under magnification. In fact, the finishing of the cal. 9ST1 might seem ordinary at a glance, but it is surprisingly unique up close. Instead of the usual decoration typical of high-end Swiss brands, the cal. 9ST1 is finished in a manner that distinctively GS.

In fact, the style of decoration brings to mind standard GS movements, except that those are decorated in an industrial manner. The cal. 9ST1, on the other hand, is finished by hand in an artisanal manner.

A closeup inspection reveals that the finishing is impressively well done. The decoration is so fine that the watch catches the light even at arm’s length thank to numerous mirror-polished surfaces within the movement.

And it’s not just the quality of the decoration, but the magnitude of it. Because the movement is extremely skeletonised – you can see right through the watch at some points – the sheer surface area that requires decoration is vast, making the thoroughness of the finishing even more admirable.

The balance wheel is polished and beveled on both the front and back

One of the most notable aspects of the decoration is the bevelling, which is done at an almost 45-degree angle, instead of the rounded anglage favoured by Swiss watchmakers. These flat bevels – which are evidently finished by hand – suit the contemporary, mechanical aesthetic of the watch well.

Interestingly, though most of the bevelling on the bridges is flat, other components still sport the a more traditional European type of finishing. Rounded, polished bevelling can be found on several smaller components visible on the front and back.

The decoration is also paradoxical in a manner that sets it apart from its peers – and perhaps reflects the no-expense-spared approach to quality that is recognisably Japanese. While most movements have finer finishing on bigger, easier-to-see parts, the Kodo instead has more elaborate finishing on its smaller components. The smallest bridges, for example, have rounded bevelling, which is apparent on the bridge for the the remontoir as well as slender bridges under the dial.

The thoroughness of the finishing is evident in parts that are even smaller – and that holds true for even some unexpected components. For instance, the unique six-slot screws are chamfered on all interior and exterior edges. Each screw is an achievement in itself considering there are 12 inner edges along the six slots, as compared to just two edges for a conventional slotted screw – and dozens of screws within the movement.

The bridge at one o’clock even has sharp inward angles along its edges

The past and future

Evidence of the past – and possibly the future – of the Kodo were on show at W&W and they were certainly intriguing. Take for instance the prototype movement exhibited in the Grand Seiko’s booth that was entirely different in shape – it was an oblong, form movement – but incorporates the same tourbillon and remontoir found in the Kodo.

“This prototype allowed us to confidently set a direction and begin designing the T0,” says Mr Kawauchiya, “It is a very memorable movement for me.”

“The oblong prototype movement was one of the very earliest prototype made the year after I came up with the mechanism in 2012, and it was my first experience designing a movement of any kind,” explains Mr Kawauchiya.

“[The oblong movement] was the first job for me and Ishihara. In order to shorten the development period of the Kodo, we used parts from existing movements as much as possible, but I asked Ishihara to join as a designer because I wanted the appearance of the prototype to be as beautiful as possible, even if it was only for internal presentation. You can already see in this prototype elements that would lead to the T0 and 9ST1, like the colours for example.”

“With this prototype, we were able to confirm that a constant-force tourbillon as one unit on a single axis could achieve high precision, leading us to see the potential in the sensual value of the 16-beat rhythm [of the balance],” adds Mr Kawauchiya, “And the use of ceramic for the stop wheel was also an idea that came from this prototype.”

The Kodo also points to where GS is going.It’s worth mentioning that the watch was developed by an elite group of Grand Seiko’s watchmakers and designers who will be part of the Atelier Ginza, a recently-established workshop located in Tokyo that is separate from the Micro Artist Studio in Shiojiri, traditionally the origin of the highest-end watches of the Seiko Group brands.

“Atelier Ginza is a place where you can experience the craftsmanship of the Seiko Group,” says Mr Kawauchiya, “Our founder, Kintaro Hattori, believed that ‘Good products always win the patronage of consumers’.

“Atelier Ginza inherits this strong belief and it is a place where the best craftsmen and women and designers aim to create watches that are unparalleled in their craftsmanship,” he adds, “And it is in Ginza, the district where Kintaro Hattori founded Seiko.”

Takuma Kawauchiya wearing the Kodo. Image – Grand Seiko

Finally, I noticed that the constant force mechanism inside the Kodo is protected by Japanese patent JP2015072254A of 2014. But there was another patent filed two years later in Switzerland, CH710863B1, which appears to be an extension of the original constant force construction but instead applied to a multi-axis tourbillon.

When asked to comment on the Swiss patent, Mr Kawauchiya is enigmatic. “Thank you for taking a look at our patent. It was a very natural idea for me to apply the original one-unit, single axis structure to multi-axis carriages,” he says, “However, it only means that we have applied for such a patent, and unfortunately I cannot tell you about our future plans at this moment.”

Conclusion

The Kodo Constant-Force Tourbillon is an ambitious watch, but it is executed to the highest level. It demonstrates a high level of attention to detail from construction to decoration, while also reflecting the manufacturing prowess of the Seiko Group, a feature that sets it apart from other watchmakers in this segment, most of which are smaller-scale operations.

In addition to its technical qualities personified by the remontoir and tourbillon, the Kodo demonstrates the brand’s courage in reimagining its design language. The result might not be for everyone – there will only be 20 examples of the Kodo in any case – but it is notable that the brand is venturing into territory, especially since GS has historically been conservative in terms of design.

Along with Atelier Ginza, where according to Grand Seiko “an elite group of watchmakers and designers will gather to create world’s finest watches”, the Kodo is a sign that GS is serious about mechanical haute horlogerie. It is certain that the Kodo will not be the last high-end mechanical complication from GS.

Key facts and price

Grand Seiko Kodo Constant-Force Tourbillon
Ref. SLGT003

Diameter: 43.8 mm
Height: 12.9 mm
Material: 950 platinum and Brilliant Hard Titanium
Crystal: Sapphire
Water resistance: 10 bar

Movement: Cal. 9ST1
Functions: Hours, minutes, dead-beat seconds, tourbillon with constant-force mechanism 
Winding: Manual wind
Frequency: 28,800 vibrations per hour (4 Hz)
Power reserve: 72 hours

Strap: Calf strap with platinum folding buckle, and additional double-sided crocodile strap

Limited edition: 20 pieces
Availability: Starting October 2022 from Grand Seiko’s retailers and boutiques
Price: US$350,000; or 40 million Japanese yen before tax

For more, visit grand-seiko.com.

Having enjoyed several years of double-digit growth in its biggest markets outside of Japan, Grand Seiko is continuing to hone a marketing and distribution strategy inspired by its Swiss peers. One of the key planks of its brand development has been to vertically integrate its sales channels, with Asia being the latest to join the mothership.

Headquartered in Singapore, Grand Seiko Asia-Pacific is a newly established entity that will take charge of sales and marketing of the brand in the region. Grand Seiko Asia-Pacific becomes the company’s third regional subsidiary, after those covering Americas and Europe, both amongst the brand’s most important markets outside of Japan.

The Grand Seiko boutique in Place Vendome, Paris

The Asia-Pacific division of Grand Seiko no doubt develop the brand along similar lines as its counterparts in Europe and the United States. The senior managers in both the Americas and Europe are Omega alumni, with the head of the American operations also being the brand’s Global Strategy Officer. Unsurprisingly, Grand Seiko has embarked on a game plan centred on brand boutiques in upscale locations as well as limited edition models, mirroring the familiar approach utilised by many of its Swiss rivals.

The newly-established Asia-Pacific operation is a joint venture between Seiko Watch Corporation and Thong Sia, the Hong Kong-based company that was the longtime Asian distributor for Grand Seiko (as well as other Seiko brands). It is chaired by Akio Naito, whose main job is President of Seiko Watch Corporation. And the company’s operations are overseen by Yoshikatsu Kawada, who is also also Executive Vice President of Seiko Watch Corporation, while the Regional Brand Director is Ida Idris-Low.

Long a leading player in the arena of high-end quartz watches, Grand Seiko’s flagship offering is the 9F quartz movement that is built with an attention to detail comparable to that of its mechanical calibres. Beyond the almost-artisanal production, 9F movements are all about accuracy – the standard movements are rated to within 10 seconds a year.

Now Grand Seiko a limited edition equipped with a specially-adjusted 9F calibre, the Heritage Collection 44GS 55th Anniversary SBGP017 “Blue Clouds”. Signified by the star emblem on the dial, the movement within is regulated to run within five seconds a year – an average of less than a half second deviation a month.

Initial thoughts

Watches with colourful, textured dials are almost the norm at Grand Seiko, which has rolled out enough limited editions that such watches seem almost more common than their plain dial counterparts. The SBGP017 dial has a familiar texture, so at first glance it seems like yet another Grand Seiko limited edition.

But a closer look reveals the fact that the SBGP017 is unusual. For one, it’s quartz. Grand Seiko quartz watches rarely have patterned dials and when they do, the dials typically have motifs made up of repeating symbols. In contrast, the abstract pattern found on the SBGP017 is similar to that found on Grand Seiko’s mechanical and Spring Drive models. Put another way, the SBGP017 is an atypical Grand Seiko limited edition because it’s quartz but has the aesthetic of a mechanical watch.

And then there’s the open case back, which is uncommon for a quartz Grand Seiko; only a handful of limited editions in the past had display backs. It might seem to be an odd thing to have on a quartz watch, but this is far from an ordinary quartz movement. Not only it is elaborately constructed, it is also attractively finished. The bridges are gilded and striped, while the screws are blued, making this one of the best decorative quartz movements at any price.

Specially adjusted

First seen on the Spring Drive 20th Anniversary SBGC231 and SBGA403 launched three years ago, the dial texture on the SBGP017 is intended to evoke lion’s mane. But the fine, irregular pattern also brings to mind cumulus clouds – the puffy, white sort – and that is exactly what the SBGP017 is meant to do. According to Grand Seiko, the dial texture and colour are inspired by the “blue-tinged clouds found in the Shinshu region” where the Shinshu Watch Studio is located.

The sky-blue dial is complemented by a blued-steel seconds hand as well as an applied “GS” logo in dark blue, which is unusual on a watch dial although the blue emblem is widely used in the brand’s stores and on its accessories

But fans of the brand will no doubt have seen many such textured dials before, so the highlight is the back where the cal. 9F85 is visible in all its glory.

Grand Seiko’s top-of-the-line quartz movement, the cal. 9F85 has an hour hand that can be set independently without stopping the seconds, making changing time zones when travelling a breeze. The independent hour hand is especially useful for a high-accuracy quartz watch, since it means the time setting isn’t lost when changing time zones.

In addition, this is not just a standard 9F movement, but a specially-regulated example that boasts a tighter annual accuracy range of within five seconds a year, as compared to the 10 seconds of the conventional calibre.

Fittingly, the cal. 9F85 is decorated better than almost all typical quartz movements. Its striped and bevelled bridges are finished in a similar manner to the earlier generation of mechanical and Spring Drive Grand Seiko movements – done industrially but neatly in other words – although the gilt finish is unusual, since Grand Seiko movements are usually rhodium plated. And the blued steel screws are a pleasing touch that add to the visual richness of the movement.

Key facts and price

Grand Seiko Heritage Collection 44GS 55th Anniversary Limited Edition
Ref. SBGP017

Diameter: 40 mm
Height: 10.7 mm
Material: Steel
Crystal: Sapphire
Water resistance: 100 m

Movement: 9F85
Features: Hours, minutes, seconds, date, and independently-adjustable hour hand
Winding: Quartz
Power reserve: 3 years
Accuracy: +/- 5 seconds per year

Strap: Steel bracelet

Limited edition: 2,000 pieces
Availability: Starting July at Grand Seiko boutiques and retailers
Price: 440,000 Japanese yen

For more, visit grand-seiko.com.