My Eastern Watch Collection: Grand Seiko Evolution 9 Spring Drive U.F.A. Ushio 300 Diver SLGB023 (similar to SLGB025)

“The movement features a regulation switch that can be used during
after-sales service to correct any divergences in accuracy that may be
caused over long periods of use. Due to the brand’s long term experience in Spring Drive technology, they understand the characteristics caused by the slight strain that
remains after the crystals are artificially aged. Hence, they are able to compensate for subtle deviations in vibration frequency that
come with ongoing aging. The regulation switch can be seen in the image on the right.”

“To create a movement with a low center of gravity, a single thin barrel with the Magic Lever and crank wheel offset from the center of the movement, have been
adopted. The movement maintains its low center of gravity while
simultaneously ensuring a power reserve of approximately 72 hours, its strength and durability are ensured by the one-piece Center Bridge. Grand
Seiko was able to create its smallest diver’s watch of any kind, with a
case diameter of just 40.8 mm.”

“The exterior of Caliber 9RB1 is meticulously finished and
reflects the natural beauty of its birthplace, Shinshu, an area more
commonly known today as Nagano Prefecture. The design itself draws
inspiration from the gentle frost that covers the trees during the
severe winters of this mountainous region. An eye-catching feature of
these frosts is the hypnotic, all-encompassing glow emitted from the
layer of frost due to its peculiar, rugged texture. The movement’s
bridge design represents the frost and is finished with a neutral-toned
sandblast coating that achieves a calm but elegant radiance. The edges
of the bridge emit a sharp glow with light captured from any direction,
accenting the design with a vivid and profound brilliance. The
oscillating weight is designed with the engraving “Ultra Fine Accuracy”.”

The Watch

At its core, the SLGB023 is a professional-grade dive watch designed to meet the demands of serious underwater use while maintaining the refinement expected from a luxury timepiece. The watch features a case measuring 40.8mm in diameter, 12.9mm in thickness, and 48.5mm lug-to-lug. These dimensions make it the most compact modern Grand Seiko diver currently available and address one of the few criticisms often directed at earlier models in the collection. 

The overall design is unmistakably Evolution 9. Sharp facets, broad hands, deeply sculpted indexes, and a highly legible layout create an instrument-focused appearance without sacrificing elegance. The ceramic bezel insert provides both durability and visual sophistication, while the 120-click unidirectional action offers the precision expected of a professional dive watch. With a water-resistance rating of 300 meters, a screw-down crown, and a screw-down caseback, the SLGB023 possesses credentials that extend well beyond recreational diving. 

Despite these impressive specifications, the watch never feels overly technical or utilitarian. Instead, it achieves the difficult balance of being a genuine tool watch that also feels perfectly at home in a luxury collection.

The Material

Grand Seiko has chosen High-Intensity Titanium for both the case and bracelet, a material that plays a significant role in the watch’s overall appeal. Compared to conventional stainless steel, High-Intensity Titanium is approximately 30 percent lighter while remaining highly resistant to corrosion and daily wear. This reduction in weight dramatically improves comfort, particularly on a sports watch designed to be worn for extended periods. 

What makes Grand Seiko’s implementation particularly impressive is the quality of finishing achieved on the titanium surfaces. Titanium is notoriously more challenging to finish than steel, yet the SLGB023 displays crisp transitions between brushed and Zaratsu-polished surfaces. The mirror-polished facets reflect light with remarkable clarity, creating a level of sophistication rarely associated with dive watches. Every angle of the case demonstrates the meticulous craftsmanship that has become synonymous with the Grand Seiko name. 

The combination of lightweight construction and luxurious finishing gives the SLGB023 a unique identity. It feels substantial enough to convey quality, yet light enough to disappear on the wrist during daily wear.

The Dial

If the movement is the technical heart of the watch, the dial is unquestionably its emotional centerpiece. The SLGB023 features a blue variation of Grand Seiko’s “Ushio” dial, a design inspired by the ocean currents and tidal waters surrounding the Japanese archipelago. The word Ushio translates to “tide” in Japanese, and the textured surface captures the movement and energy of the sea in a manner that only Grand Seiko seems capable of executing. 

The richness of the blue gradient immediately draws attention. Lighter tones near the center gradually deepen toward the periphery, creating a sense of depth that evokes sunlight fading beneath the ocean’s surface. Depending on the lighting conditions, the dial can appear vibrant and dynamic or dark and contemplative. This constantly changing personality keeps the watch visually engaging long after the novelty of ownership wears off.

Equally impressive is the dial’s practicality. The large applied markers feature diamond-cut surfaces that reflect light brilliantly, while generous Lumibrite application ensures excellent nighttime visibility. The broad Evolution 9 hands are instantly recognizable and exceptionally legible. Every design decision has been made with readability in mind, reinforcing the watch’s credentials as a serious diving instrument. 

The Bracelet

A luxury sports watch is only as good as its bracelet, and Grand Seiko has made meaningful improvements in this area. The titanium bracelet feels solid, refined, and exceptionally comfortable. Its finishing mirrors the quality seen on the case, featuring a combination of brushed and polished surfaces that complement the watch’s overall design language. 

More importantly, the bracelet introduces a new locking extension clasp with integrated micro-adjustment functionality. This system allows for several stages of incremental adjustment, enabling wearers to fine-tune the fit throughout the day. Additional extension capability is available for use over a wetsuit, making the clasp both practical and versatile. 

For many collectors, the updated clasp may prove to be one of the most welcome upgrades on the entire watch. It significantly enhances comfort and demonstrates that Grand Seiko continues to listen to feedback from enthusiasts and professional users alike. 

The Movement

The defining feature of the SLGB023 is the new Spring Drive Caliber 9RB1, a movement carrying the prestigious U.F.A. (Ultra Fine Accuracy) designation. With a stated accuracy of ±20 seconds per year, it ranks among the most accurate wristwatch movements powered by a mainspring currently available. As remarkable as the watch itself is, the movement is what truly sets it apart from its competition.

The 9RB1 is the latest evolution of Grand Seiko’s unique Spring Drive technology, which combines traditional mechanical energy storage with electronic regulation. Powered by a mainspring but governed by a quartz-referenced glide wheel system, the movement delivers extraordinary precision while retaining the emotional appeal of a mechanically driven watch. The signature smooth sweep of the seconds hand remains one of the most mesmerizing sights in modern horology. 

The movement offers approximately 72 hours of power reserve and incorporates advanced thermal compensation and individual calibration processes to achieve its exceptional performance. While many brands focus on marginal improvements in chronometric performance, Grand Seiko has effectively redefined expectations for what a mainspring-powered sports watch can achieve.

Above is a photo of a watch in the dark. The illumination from the LumiBrite paint is clearly visible and effective. As there is no date complication on the watch, no hour marker was needed to be sacrificed. The symmetry is perfect.

The Wearing Experience

The true brilliance of the SLGB023 becomes apparent once it is worn. Despite its professional diving specifications and impressive technical capabilities, it feels remarkably comfortable and balanced on the wrist. The reduced dimensions represent a transformative improvement over previous Grand Seiko divers, making the watch suitable for a much wider range of wrist sizes.

The lightweight titanium construction ensures that the watch never feels cumbersome, while the ergonomic Evolution 9 case design helps it sit naturally against the wrist. Combined with the micro-adjustment clasp, the SLGB023 provides a level of comfort that encourages all-day wear. Whether paired with casual attire, business clothing, or outdoor gear, the watch adapts effortlessly to its environment.

What ultimately makes the SLGB023 special is its ability to satisfy on multiple levels simultaneously. It is a serious dive watch, a technological showcase, a beautifully finished luxury product, and an exceptionally comfortable daily companion. Few watches manage to excel in all of these areas at once. The Grand Seiko Evolution 9 Spring Drive U.F.A. Ushio 300 Diver SLGB023 does exactly that, making it not only the finest Grand Seiko diver to date, but also one of the most compelling luxury sports watches currently available. Below is a video of the watch on my wrist.

The Purchasing Experience

Unlike most quality ADs, the set up of the Daimaru Sapporo Department Store watch section is rather open. Nonetheless, it is a multi-brand AD carrying Rolex, Tudor, Omega, Panerai, IWC, Corum, Seiko, Credor, Grand Seiko, Citizen, Campanola, Vancheron Constantin, Tissot, Hamilton, Mido, Hublot, Longines, Oris and more. You will definitely be spoiled for choice.  

To be honest, one do not need to travel anywhere else after visiting this mall. Truly, a one-stop-center.

For the purchaser, you will be directed to a comfortable sitting lounge to conduct all the necessary paperwork. Unfortunately, it is not as secluded as a standalone ADs.

Language was an issue as none of the salespersons were able to speak English properly. However, with the help of Google Translate, the message got across fine.