The term Ushio, which means "tide" in Japanese, evokes the waters that surround the Japanese archipelago, a timeless source of inspiration in Japan's culture and art.
SLGB023
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The blue dial reflects the vast expanse of the sea through a gradient that captures light streaming into the deep ocean.
The green dial draws from the tranquil beauty of shallow coastal waters near the shore.
SLGB025
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Diamond-cut, multi-faceted indexes deliver exceptional brilliance, while Lumibrite ensures superb legibility in any light.
At 40.8mm, the smallest Grand Seiko diver sits effortlessly on the wrist.
The bracelet includes a newly developed locking extension clasp with micro-adjustment.
Powered by the new Spring Drive U.F.A. Caliber 9RB1
The 9RB1 movement is hand-assembled by the highly skilled craftsmen and women of the Shinshu Watch Studio, located in a Seiko Epson facility in the city of Shiojiri in Nagano Prefecture.
This groundbreaking movement received the U.F.A. designation, standing for "Ultra Fine Accuracy." Boasting an annual accuracy rate of ±20 seconds, it is the most accurate wristwatch movement powered by a mainspring.*
* As of April 2026, based on Grand Seiko's research.
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