Nature-inspired textures are a consistent motif across Grand Seiko’s portfolio, so it comes as little surprise that the brand would choose this familiar theme for the launch of its newest dress watches, the hand-wind and mechanical Evolution 9 “Birch Bark” SLGW002 and SLGW003. 

With a dial that features a fresh take on the texture of tree bark, the Birch Bark is also noteworthy for the movement within: the first manually-wound caliber in Grand Seiko’s 9S movement family that hitherto was entirely self-winding.

The SLGW002 (left) and SLGW003

Initial thoughts

There are few things I like more than a manually wound, chronometer-grade dress watch. With this bias in mind, I am predisposed to like watches like the Birch Bark. But Grand Seiko made things easy by making it attractive as well, with a new iteration of its Evolution 9 design language that is lighter in terms of visual weight.

The big news is, of course, the thickness, or rather the lack thereof. The Birch Bark is 1.75 mm (15%) thinner than its automatic siblings like the SLGH003, answering’ calls for slimmer, dressier options in the Grand Seiko catalogue.

The watch is also 1.4 mm (3.5%) smaller in diameter, resulting in a form factor that sits comfortably on the average wrist and will slide under most shirt cuffs.

Dimensions aside, the Birch Bark in titanium feels smaller and lighter than expected due to the case material. This runs counter to expectations, since most dress watches are in precious metal.

The Birch Bark answers the call for thinner options.

In terms of value, the Birch Bark is a tale of two watches. On one hand, the SLGW003, in Grand Seiko’s proprietary hardened titanium, is a compelling option at just under US$11,000.

In terms of quality, technicality, and form factor there are few direct peers; the closest is probably Omega’s manually wound De Ville Trésor, which almost just as thin and also features twin mainspring barrels and a proprietary escapement. But the Birch Bark arguably offers more in terms of design and finishing.

On the other hand, the US$45,000 price point of the rose gold SLGW002 puts it in an altogether different category.

Despite its 80-piece limitation, it’s hard to find a justification for this pricing, which is nearly 50% higher than a Patek Philippe ref. 6119R, for example. Precious metal watches form the minority of Grand Seiko’s output, so the SLGW002 is destined for a niche audience of brand enthusiasts.

The rose gold SLGW002 features solid gold dial markers, denoted by a star emblem at six o’clock.

Evolution 9, evolved

Despite its refined design language and the fact that it was the brand’s only completely new reference to debut at Watches & Wonders, the Birch Bark is nonetheless instantly recognisable as a Grand Seiko. The brand’s Evolution 9 design language has been nipped and tucked, resulting in something that feels both familiar and new.

This is immediately apparent on the dial, which features a horizontal Birch bark pattern that distinguishes it from similar watches like the SLGA009 White Birch which features a vertical pattern. To my eye, the horizontal pattern more closely resembles actual Birch tree bark than did previous riffs on this theme.

Second, the dial markers, which otherwise retain the signature Evolution 9 style, have been elongated and slimmed down. This has the effect of making the dial appear larger, ensuring the watch will have presence on the wrist despite its tangibly smaller diameter.

The Birch bark pattern has evolved to look even more like tree bark.

The Birch Bark’s case is adapted from its sportier SLGH-series siblings, resulting in a case that is more richly detailed than is typical for a dress watch. During this transition from casual watch to dress watch, the forms were elongated, making the polished bevels stand out even more.

This is particularly apparent on the bevels on the insides of the lugs, which, benefit from the absence of a bracelet. If I were to change anything about the case, it would be the drilled lug holes, which feel out of place on a dress watch and distract from the angular terminal points of the lugs.

The slim bezel and downturned lugs are finely beveled.

The 9SA4

This Birch Bark’s slimmer physique is made possible by the new cal. 9SA4, the first manually wound movement in the 9S family, and the first to eschew a date complication.

Largely similar to its automatic siblings, the movement features two barrels that power Grand Seiko’s proprietary dual impulse escapement for 80 hours; an impressive number for watch that runs at 5 Hz, or 36,000 beats per hour.

This is possible thanks to the efficiency of the dual impulse escapement, which provides a direct, radial impulse to the balance in one direction, and an indirect, sliding impulse in the other.

These characteristics make it something of a hybrid between the co-axial escapement commercialised by Omega, and the lever escapement that otherwise dominates the industry. The new movement also shares the free-sprung balance, and proprietary overcoil, used by other movements in the 9S family.

Another key difference between the cal. 9SA4 and its siblings is the power reserve indicator visible through the case back. This is another nice touch, nearly as convenient as a dial-side indicator while keeping the dial uncluttered.

Conveniently, the power reserve mechanism also fits neatly in the space vacated by the automatic winding system, preserving the movement’s minimum thickness.

The new cal. 9SA4 shares the full balance bridge architecture, free-sprung balance, overcoil hairspring, and dual-impulse escapement with other calibers in the 9S family, but the power reserve indicator is unique to the cal. 9SA4.

The existence of the cal. 9SA4 is also promising in another dimension; it puts the brand within striking distance of offering a manually wound chronograph caliber.

While any chronograph built on this platform would likely use a dial-side module, forgoing some of the genre’s typical charm, it would nonetheless allow for the creation of something slightly thinner than the cal. 9SC5-powered Tentagraph.

In terms of finishing, the cal. 9SA4 is an industrial product done well. The movement features wide bevels and countersinks that, to the naked eye, catch the light well. The striping is also refined, and extends to the balance bridge itself, unlike the Rolex 1908’s cal. 7140.

Of course, under magnification it’s clear that the bevels are machined, but that’s fair in the context of the pricing (at least for the titanium ref. SLGW003).

The movement is also fairly generic in terms of its architecture, with little to identify it as a distinctly Japanese product in the way that some of the brand’s higher-end Spring Drive movements often do.

A bird in the hand?

When Grand Seiko is at its best, the brand demonstrates admirable attention to detail, and that is apparent as soon you wind the Birch Bark.

A new winding click was developed to give the watch a more vintage feel, with larger, more defined clicks. Compared to the automatic cal. 9SA5 on which the cal. 9SA4 is based, the winding feel is more tactile and satisfying.

The new winding click is bird-like in its shape

That Grand Seiko (as well as Seiko with the Credor line) incorporates elements of nature into its dial patterns is well known, but the brand’s engineers also do the same with movements. The “mountain range” full bridge of the Grand Seiko 8 Day cal. 9R01 is one example.

The same has been done in the cal. 9SA4, albeit in a more subtle manner. The shape of the winding click is meant to resemble the head of a particular type of wagtail, a a bird that is native to Morioka. It’s the nearest major city to Shizukuishi, the town that’s home to the Grand Seiko Studio where the cal. 9SA4, and all other mechanical Grand Seiko movements, are made.

This fits neatly into the woodland theme of the watch; perhaps too neatly. While the click is certainly bird-like, it’s not substantially different in form to other winding clicks used in the industry, particularly that of the Lange L941.1, making the “wagtail” narrative feel a bit forced.

Concluding thoughts

Whether one is a fan of Grand Seiko or not, the Birch Bark should appeal to anyone who appreciates a highly technical chronometer-grade dress watch. For the brand’s devoted fans, it is a strong answer to the call for slimmer options.

Visually attractive, satisfyingly tactile, technically differentiated, and well-priced (at least for the SLGW003), the Birch Bark is one of the stand-out launches of the year.

Key facts and price

Grand Seiko Evolution 9 Manual-Winding Hi-Beat 36000 “Birch Bark”
Ref. SLGW002 (rose gold)
Ref. SLGW003 (titanium)

Diameter: 38.6 mm
Height: 9.95 mm
Material: Titanium or rose gold
Crystal: Sapphire
Water resistance: 30 m

Movement: 9SA4
Functions: Hours, minutes, and seconds
Winding: Manual
Frequency: 36,000 beats per hour (5 Hz)
Power reserve: 80 hours

Strap: Alligator strap with folding clasp

Limited edition: 80 pieces for SLGW002, regular production for SLGW003
Availability: At Grand Seiko boutiques and retailers starting August 2024
Price: US$10,700 (SLGW003); US$45,000 (SLGW002)

For more, visit grand-seiko.com