Grand Seiko’s first-ever mechanical chronograph is the Grand Seiko Evolution 9 Tentagraph SLGC001 watch, or Grand Seiko Tentagraph, for short. A Watches & Wonders 2023 novelty, the Tentagraph is an extension of the Evolution 9 collection that debuted at last year’s fair. Fans of horological trivia will want to know that the name, Tentagraph, is a portmanteau that refers to the Ten beats per second frequency of the movement, its Three days of power reserve, and that it’s an Automatic Chronograph.


Brand: Grand Seiko
Model: Evolution 9 Tentagraph SLGC001
Dimensions: 43.2mm-wide and 15.3mm-thick
Water Resistance: 10 bar
Case Material: “High-intensity titanium” case
Strap/Bracelet: “High-intensity titanium” bracelet
Crystal/Lens: Sapphire crystal
Movement: Grand Seiko 9SC5
Power Reserve: 72 hours with the chronograph in operation
Operating Frequency: 5Hz
Price & Availability: $13,700, available from June 2023

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Grand Seiko has shown its expertise in the field of chronographs with its Spring Drive chronographs such as the SBGC001 — arguably the most highly engineered chronograph wristwatch in its segment that never really caught on because of its peculiar design. We have extensively reviewed that watch, and Spring Drive technology, here. The SLGC001, however, is not a Spring Drive watch but a fully mechanical one.

Based on the Grand Seiko 9SA5 high-beat caliber, the 9SC5 beats ten times per second — that’s a 5Hz operating frequency, the same as that of the El Primero and just a handful other exotic chronographs. Grand Seiko prides itself for the Tentagraph’s full 3-day power reserve that holds even with the chronograph running the whole time. In fact, the Japanese watchmaker goes so far as to say that it is the longest power reserve for any 10-beat chronograph in the industry today. All 5Hz chronograph watches with extended power reserves in recent memory, like those by Omega, Czapek, and Parmigiani Fleurier, had between 60 and 65 hours of power reserve.

The Grand Seiko Tentagraph is also subjected to what the brand refers to as a “new and longer testing procedure,” explaining: “As with all Grand Seiko mechanical movements, the Tentagraph’s time-of-day accuracy is assessed in six positions and at three temperatures over 17 days but, in addition, there are three more days of testing during which the accuracy is assessed in three positions while the chronograph is in operation. Thus, in total, each Tentagraph movement is tested for 20 days to ensure that it meets the Grand Seiko Standard of +5 to -3 seconds per day.”

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The Grand Seiko Tentagraph has a 43.2mm-wide and 15.3mm-thick case and its bracelet is crafted from “high-intensity titanium” that is 30% lighter and, according to Grand Seiko, is more scratch resistant than stainless steel. The dial features Grand Seiko’s signature Mt. Iwate pattern inspired by the contours of the nearby mountain visible through the windows of the Grand Seiko Studio Shizukuishi where the Tentagraph watch is hand-assembled and adjusted.

The Grand Seiko Evolution 9 Tentagraph SLGC001 watch is priced at $13,700 and will be available starting in June 2023. You can learn more at the brand’s website.

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