The Evolution 9 Collection was born in 2020, incorporating the new Grand Seiko design grammar. The latest addition to this series is a model equipped with a manual-winding high-beat movement, featuring a navy blue dial that evokes the image of birch bark illuminated by moonlight. Watch enthusiast and writer Shun Horiuchi delves into this piece.
Photographs & Text by Shun Horiuchi
[Article published on January 21, 2025]
What is the design code for the Evolution 9 Collection?
The "Evolution 9 Collection" is a series that was introduced in 2020. Its distinctive feature is its design based on the "Evolution 9 Style." This style is a further development of the "Grand Seiko Style" established with the "44GS" in the brand's lineage.
The main features are as follows:
- The shape from the case side to the lug is relatively straight, with the lower end of the lug cut at an angle (Seiko calls it a reverse slope).
- The indexes on the dial are massive and give a powerful impression.
- In addition, the thickness of the hands is balanced with the indexes. The tip of the hour hand is cut to be smooth.
- Refined balance of the thickness of the hour and minute hands
- The bracelet design code has been refined (although this model is a strap type).
SLGW007 exterior details
The Ref. SLGW007 from the Evolution 9 Collection that we will be taking a closer look at this time is a new model that truly embodies the design codes of the Evolution 9 style, and it is no exaggeration to say that it features a birch-textured dial that is now representative of Grand Seiko. (Editor's note: As birch forests grow in abundance near Grand Seiko's workshops in Iwate and Nagano prefectures, the brand offers models with dials that feature a silver-white embossed pattern based on the bark of this tree.)
A new Grand Seiko model, released in 2025, equipped with Caliber 9SA4. The dial features a distinctive embossed pattern and is colored navy blue, evoking the image of birch bark illuminated by moonlight. Manual winding (Caliber 9SA4). 47 jewels. 36,000 vibrations per hour. Power reserve of approximately 80 hours. Stainless steel case (diameter 38.6mm, thickness 9.95mm). Water resistant for everyday use. Price: 1,342,000 yen (tax included). (Inquiries) Seiko Watch Customer Service (Grand Seiko) Tel. 0120-302-617
The dial features silver metallic indices and hands, and the GS logo provides a nice contrast to the navy dial, while also ensuring excellent visibility.
時計本体の厚さは風防込みで9.95mmとギリギリではあるが10mmを切っており、ドレスウォッチのような雰囲気も持つため、フォーマルなシチュエーションでも違和感なく使えるだろう。グランドセイコースタイルの原型となった1967年発表の44GSはそもそも手巻きであり、新型手巻きムーブメントであるCal.9SA4を搭載した本機は、最初にデビューし、Cal.9SA4のベースとなった自動巻きCal.9SA5搭載モデルのどの作品よりも、オリジナルの44GSに近い存在と言えそうだ。
The case is made of stainless steel. It is not made of any JIS-standard material, but rather is a Grand Seiko-exclusive stainless steel whose composition and manufacturing method are not disclosed. The finish is truly "GS quality," with high precision on every surface of the case, both flat and curved, and crisp edges. The contrast between the satin and polished surfaces is also stunning, a feat that is surely the result of high-precision CNC machining.
The back of the lugs are blunt, which is apparently a good decision, as it takes into consideration the impact on the wrist. If the back of the lugs had the same sharp edges as the front, it might cause some damage to the wrist.
When I look at the case, I especially look at the case side between the lugs and the inside of the lugs. This is because this is a very difficult area to work on, and on watches with leather straps, this area, especially on the 6 o'clock side, is very visible. The case of this model is perfectly polished and I felt it lived up to its price of 1,342,000 yen (tax included).
The sapphire crystal with anti-reflective coating on the inside has a boxy shape that matches the character of this model. The bezel from which the crystal rises has a hairline pattern from 12 o'clock to 6 o'clock, which contrasts with the polished bezel slope and emphasizes the three-dimensional effect.
The lugs are shaped in a large arc from the side of the case, reaching the end of the lug without descending too far toward the case back. The lug holes are through, which is relatively rare in the high-price range, but is useful when changing straps. However, these days, many watches use straps that can be changed with one touch, so blind holes are not a problem. Many Grand Seiko models seem to have through holes, and I thought this was a kind of identity, but there are exceptions.
A distinctive feature of the Evolution 9 collection is the additional facet on the inside of the lugs, adding a touch of delicacy and accent to the overall simple and sturdy case design.
The navy dial features a pressed, horizontally textured surface reminiscent of birch bark. Relatively large indices sit atop these uneven surfaces, and if placed without careful consideration, they might not be flush with the surface. However, the indices are attached after a smooth, lacquered finish, demonstrating a high level of precision. The indices are not glued on, but each has a foot that penetrates the dial.
The indices are also of GS quality, naturally. They have a crisp shape, with the 12 o'clock position being particularly large and eye-catching. The hour and minute hands, designed to balance out these massive indices, also have a powerful design, with a satin finish on the surface and a polished side. The hour hand has a line engraved in the center, a characteristic of the Evolution 9 style. The second hand, including the counterweight, is uniformly polished, creating a three-dimensional shape.
It is also worth noting that the clearance between the three hands extending from the center has been reduced and the distance between the dial and the inside of the crystal has been optimized, resulting in a sense of luxury.
The strap is navy blue to match the dial, and is made of Japanese calfskin with a unique grain. It is very supple. The buckle is a folding buckle, which is also GS quality, and is truly impressive.
A newly designed large hand-wound movement, Cal. 9SA4
Now, a major factor that shapes the character of this watch is that it is equipped with the manual winding movement Cal. 9SA4, which was announced by Grand Seiko last year.
The Caliber 9SA4 is 31mm in diameter, a "hand-wound, three-hand" movement with a size of around 13 lignes, something that was rarely produced in the watch industry until recently. It's a high-beat movement with a frequency of 36,000 vibrations per hour, which is said to contribute to improved precision, and the balance cock (balance cock) that holds the balance is sturdy and double-supported. Large screws are fixed to both ends of the balance cock, and smaller gold screws can be seen on either side of those. These screws are used to adjust the balance cock's position. Adjusting the position is not done by pushing the jewel into the hole, but by simply moving the entire balance cock up and down, which is a welcome design for watchmakers.
The fixing screw for the gear continuing from the ratchet wheel of the barrel has three slits, which indicate that it is a reverse thread, and this is also a design that is friendly to the watchmaker who actually maintains the movement. (Editor's note: Reverse threads, which have a different direction for loosening and tightening than the standard screws, have been used in watch movements to prevent them from loosening due to the rotation of the gears. Three slits are sometimes made on the top surface to identify reverse threads.)
On the other hand, the movement's bridges are large and have many jewels. It seems that it would be quite difficult to actually align all the axes with these jewels while placing the bridges, and it may be difficult to perform an overhaul. It is also stated that the bridges use a whopping 47 jewels. It appears that many jewels are used in the gear train for the power reserve display.
As has been discussed before, this movement features a distinctive kohaze (thread lock). The kohaze refers to the ratchet mechanism that holds the gears in place to prevent the mainspring from unwinding when it's wound. The kohaze on this watch resembles the wagtail, the bird that inspired it, inserting its beak into the gear. The birch dial and the wagtail, both of which can be seen around Grand Seiko Studio Shizukuishi, seem to share a connection, which will delight owners. Furthermore, the spring that presses the kohaze onto the gear (the ratchet wheel) is a leaf spring rather than a simple wire spring, and its design is similar to that used in pocket watches. Many fans of hand-wound movements are particular about the kohaze, and the Cal. 9SA4 will likely be highly satisfying.
While the Cal. 9SA4 design retains some of the design harkens back to the pocket watch era, it is a cutting-edge movement currently being produced. Its parts are CNC-machined, and most of the decoration appears to be done by machine. For this reason, the chamfered edges of the bridges are precisely cut to a C, and their lustre clearly indicates that they were carved with sharp tools.
What I found clever was the stripe pattern, which at first glance looks like a Côtes de Genève. The tool mark feed is perfectly consistent, suggesting it is a CNC finish, but the stripes are relatively narrow, and when viewed with the naked eye, they reflect a soft light, which is quite appealing.
This watch is a high-beat movement that beats at 36,000 vibrations per hour and boasts a power reserve of approximately 80 hours, meaning that once the mainspring is fully wound, it will continue to run for more than three days, and you can also expect high precision that meets the GS standard. However, the click of the push-button is so pleasant that you may want to wind it every day.
About the Dual Impulse Escapement
One of the technologies that allows the Cal. 9SA4 to achieve a power reserve of approximately 80 hours is the use of a dual impulse escapement. This watch does not use the typical club tooth lever (Swiss lever) escapement. For more details, please take a look at the video on Grand Seiko's official website (Reference:9S Mechanical 25th Anniversary | 25 Years of Evolution and Innovation - Vol. 13 The Revolutionary Dual Impulse Escapement).
While a typical club-tooth lever escapement only has an impulse jewel on the balance, this model also has a pallet jewel. While the pallet appears to be an English lever at first glance, this escapement differs in that it has two jewels on the balance. This means that the impulse from the escape wheel is transmitted in two ways: directly to the balance and via the pallet, a process described as "dual impulse." Expanding on this, it appears to be an extension of Omega's coaxial escapement, and depending on how you look at it, it could also be said to have a detent with a safety function and an automatic start function when the mainspring is wound. This is likely the result of the development of complex, high-precision escape wheels and pallets using MEMS technology. I believe that this escapement's debut in 2020 had a significant impact on the global mechanical watch industry.
In what situations should you wear this watch?
Finally, let's consider the situations in which this watch will be used. As a thin, hand-wound watch with a small case diameter of 38.6mm, it should fit into a relatively tight cuff. Of course, it is also a daily watch that can be used for both business and casual occasions, and is perfectly suitable for formal occasions. If we were to imagine the type of user the manufacturer has in mind, it would likely be an experienced watch enthusiast who owns multiple mechanical watches. For enthusiasts who wear many watches on a daily basis, the lack of a date display would also be a desirable feature.
From this perspective, this watch is worthy of consideration even for discerning watch enthusiasts. The latest Grand Seiko, the "Evolution 9 Collection" Ref. SLGW007, is especially noteworthy for those who have not previously had much interest in Japanese watches.
