Grand Seiko Novelties: Ushio 300 Diver with U.F.A. Caliber
With the SLGB023 and SLGB025, Grand Seiko is expanding its Evolution 9 collection at Watches & Wonders 2026 with two new Spring Drive diver’s watches that combine precision, functionality, and design depth in a clean, modern form. At the heart of these watches is the new U.F.A. Caliber 9RB1 — one of the most precise mainspring-driven movements in the world.
With a rate accuracy of ±20 seconds per year, Grand Seiko is now consistently applying its highest level of precision to the realm of sporty diver’s watches. The 9RB1 caliber combines the signature Spring Drive technology with rugged everyday practicality — including 300-meter water resistance, a screw-down crown, and a unidirectional rotating bezel.
SLGB023 “Ushio 300” – Inspired by the Sea
The SLGB023 draws its inspiration right from its name: “Ushio” means “tides” and refers to the waters surrounding Japan. The deep-blue dial picks up on this idea and interprets it with a subtle color gradient that reflects the depth of the ocean and the light falling upon it. At the same time, functionality remains central — the clear readability meets the high standards required of a professional diver’s watch.
Evolution 9 – clean lines, maximum readability
Like all models in the Evolution 9 line, the new Diver watches feature striking, faceted hour markers and bold hands. LumiBrite on the hands, hour markers, and bezel ensures optimal visibility in all conditions. Function and design come together seamlessly here.
The case, crafted from high-intensity titanium, is approximately 30 percent lighter than stainless steel and measures a compact 40.8 millimeters in diameter. This makes the Ushio 300 one of Grand Seiko’s slimmest diving watches, offering exceptional comfort while maintaining a robust design.
Technology that delivers in everyday life
The Spring Drive Caliber 9RB1 offers a power reserve of approximately 72 hours and combines mechanical energy with electronic precision. It is manufactured at the Shinshu Watch Studio in Japan. The technical features are complemented by a micro-adjustment mechanism in the bracelet with an adjustment range of up to 24 millimeters — a detail that underscores the watch’s practicality.
With the SLGB023 and SLGB025, Grand Seiko demonstrates how the highest precision, functional sportiness, and Japanese design culture can be combined in a modern diver’s watch — technically sophisticated yet aesthetically clean.
