Grand Seiko · Evolution 9 Tentagraph
The model in detail
Meet the watch
The SLGC001's blue dial pattern takes inspiration from Mt. Iwate, while three counters identify it immediately as a chronograph. Behind them is the more interesting part: 9SC5, Grand Seiko's first mechanical chronograph, named Tentagraph.
The name combines the calibre's attributes: ten beats per second, three days of reserve, automatic winding and a chronograph. The 5 Hz frequency produces more frequent steps of the seconds hand. It is an architectural feature; you cannot compare the daily accuracy of different watches from frequency alone.
Grand Seiko explicitly specifies about 72 hours after a full wind even with the chronograph running. The practical question is whether you can leave the stopwatch on for an extended period. The stated reserve covers that mode for this model, but actual runtime will be shorter if it starts only partly wound.
Details and limitations
The high-intensity titanium case measures 43.2 mm across, 51.5 mm lug to lug and 15.3 mm thick. Grand Seiko lists a weight of 154 g. Those are substantial dimensions: check where the lugs end on your wrist, whether the case catches a cuff and how the pushers feel.
EnlargeOfficial SLGC001 photograph: blue dial and titanium case.
© Seiko Watch Corporation / Grand Seiko · SourceThe ceramic tachymeter bezel, luminescent hands and markers help legibility. The counters measure 30 minutes and 12 hours. Inspect them in your usual light before buying: the dial texture is attractive, but contrast remains a personal judgment.
Grand Seiko gives two accuracy ranges: +5 to −3 seconds a day is the mean result of a movement tested outside its case in controlled conditions; +8 to −1 seconds a day is the normal usage range. The test conditions differ, so do not expect the laboratory figure automatically on the wrist.
SLGC001 predates this issue of the magazine: this is a review of an existing model, not a new launch. It is interesting for its unusual combination of high frequency, chronograph and three-day reserve. Its dimensions are the main tradeoff to judge on your own wrist.
