New Releases · 2026-04-14

Grand Seiko’s SLGB023 Ushio 300 Diver brings U.F.A. precision underwater

The 40.8 mm titanium diver combines 300-metre capability with Spring Drive accuracy rated to ±20 seconds per year.

By Chronolume digest · Original English summary · Based on Grand Seiko

Grand Seiko SLGB023 Ushio 300 Diver blue dial — The blue Ushio 300 Diver, reference SLGB023. GQ Japan ↗

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This is a sourced news summary, not a hands-on review. Read the original reporting at Grand Seiko ↗

What to know

Grand Seiko introduced the blue-dial SLGB023 Ushio 300 Diver on 14 April 2026. Its 40.8 mm High-Intensity Titanium case is the brand’s smallest professional diver format to date, paired with a unidirectional bezel, screw-down crown and a locking extension clasp with micro-adjustment. The textured gradient dial evokes moving ocean tides.

Grand Seiko SLGB023 Ushio 300 Diver titanium caseback — The titanium caseback identifies the 300-metre rating and 9RB1 family. Gear Patrol via Yahoo ↗

The automatic Spring Drive calibre 9RB1 delivers a 72-hour power reserve and a stated annual accuracy of ±20 seconds. Water resistance is rated to 300 metres, while LumiBrite covers the hands, indexes and bezel. The titanium construction keeps weight to 122 grams, giving this technically ambitious Evolution 9 model a more compact and practical profile than Grand Seiko’s earlier Spring Drive divers.

At a glance

Specifications reported by Grand Seiko
reference	SLGB023
case	40.8 mm High-Intensity Titanium
movement	Spring Drive calibre 9RB1
powerReserve	72 hours
accuracy	±20 seconds per year
waterResistance	300 metres