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Grand Seiko Evolution 9 Spring Drive U.F.A. Ushio 300 Diver SLGB023

Reference SLGB023. A sheet to take with you: the numbers to check the watch against, what to look at, and what to ask. It does not authenticate anything and it does not tell you whether to buy.

Check the numbers

Measure or ask. A watch that does not match these is not necessarily wrong, but it is a question worth the answer.

Anything above marked not recorded is a gap in this catalog, not a property of the watch. Do not read a blank as a zero.

Before anything else

Grand Seiko is counterfeited far less than the Swiss names it competes with, and a 2026 titanium diver on a movement nobody else makes is not a practical fake target. The checks worth doing here are about the Spring Drive behaving correctly and the titanium being what it should be.

What to look at

1. dial Seconds hand motion
   Correct A continuous, entirely smooth glide with no perceptible step at any magnification
   Red flag Any stepping or stutter, which means the glide wheel is not running as a Spring Drive should
2. dial Power reserve indicator against actual running
   Correct Indicator tracks toward full on winding and the watch runs roughly 72 hours from full
   Red flag An indicator that sits at one end regardless of winding, or a reserve well short of 72 hours
3. case Unidirectional bezel and its ceramic insert
   Correct Turns anticlockwise only, through 120 defined clicks, with the colour fired through the ceramic
   Red flag Bidirectional rotation, a click count that does not reach 120, or a different colour showing at a chipped edge
4. crown Screw-down crown against the 300m rating
   Correct Threads and seats cleanly; the diver rating depends on it entirely
   Red flag Cross-threading or a crown that will not seat

Known issues on this reference

• A Spring Drive seconds hand GLIDES. It does not tick and it does not sweep in the eight-beats-a-second way a mechanical does. A seconds hand with any visible step is not a working 9RB1, and that is the single fastest check on this watch.
• This is the U.F.A. specification, rated to plus or minus twenty seconds a YEAR. A watch drifting seconds per day is not performing to specification and needs Grand Seiko, not a general watchmaker.
• High-Intensity Titanium is harder than the grade 5 titanium most brands use, so it should not show the soft scuffing plain titanium picks up. Unusually easy marking is worth questioning.

Parts that are commonly replaced

• Bracelet links and the diver extension are ordinary service items.
• The ceramic bezel insert is replaced after damage; ceramic chips rather than scratches, so damage tends to be obvious.

Ask the seller, whatever the watch

• When was it last serviced, by whom, and is there paperwork?
• Has the case ever been polished?
• Which parts are not original to it?
• Do you have the box, papers and the original bracelet or strap?
• Why are you selling it?
• Can I see it in daylight, and can I take a photo of the caseback?

What this sheet is standing on

The specifications above are sourced to grand-seiko.com, monochrome-watches.com. What else the catalog does not know.

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