The Grand Seiko Tentagraph SLGC001 is the brand’s first mechanical chronograph: an Evolution 9 sports watch powered by automatic Caliber 9SC5. The movement beats at 36,000 vibrations per hour and is specified to run for about 72 hours even with the chronograph operating. Its defining combination is high-beat timing and a three-day reserve, housed in a 43.2 mm titanium-and-ceramic watch.
What does “Tentagraph” mean?
Grand Seiko announced the SLGC001 on March 27, 2023, describing it as its first mechanical chronograph. The name “Tentagraph” combines four features: “TEN” beats per second, “Three days” of power reserve, “Automatic” winding, and “chronoGRAPH.” Those elements describe the watch’s movement rather than a separate chronograph technology. Grand Seiko’s launch announcement introduced the model as part of the Evolution 9 Collection.
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How does Caliber 9SC5 work?
Caliber 9SC5 is an automatic movement that can also be wound manually. It runs at 36,000 vibrations per hour—5 Hz, or 10 beats per second—and has 60 jewels. The chronograph measures elapsed time with a 30-minute counter at 9 o’clock and a 12-hour counter at 6 o’clock.
High-beat rate and three-day reserve
Grand Seiko specifies approximately 72 hours of power reserve “even when the chronograph function is in operation.” That is the notable practical claim behind the name: the stated reserve is not limited to time-only operation. The company says the caliber builds on its high-beat 9SA5 and combines a Dual Impulse Escapement with twin barrels as part of its energy strategy. These are manufacturer descriptions, not the result of independent comparative testing. Grand Seiko’s Caliber 9SC5 page gives the movement specifications and explains the name.
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- See-through case back
- Date display
- Screw-down crown
- 40mm Diameter
- Weight 178.0 g
Chronograph and date mechanisms
The chronograph uses a column wheel and vertical clutch. Grand Seiko also says the date changes through a movable date finger produced using MEMS manufacturing. The date appears between 4 and 5 o’clock on the dial.
How accurate is the Tentagraph?
Grand Seiko publishes two accuracy figures, each tied to a different context. Its current model and movement pages list a mean daily rate of +5 to −3 seconds per day, while the stated normal-use accuracy range is +8 to −1 seconds per day. The first is a mean daily rate specification; the second describes the range given for use outside laboratory conditions. Neither should be read as a guarantee that every individual watch will show exactly the same rate on every day.
Case, dial, and wearing dimensions
The SLGC001 measures 43.2 mm across, 51.5 mm from lug to lug, and 15.3 mm thick. Grand Seiko lists a weight of 154 g and a 23 mm band width. The case and bracelet are high-intensity titanium with ceramic components; the launch materials specify a box-shaped sapphire crystal with anti-reflective coating. Its listed water resistance is 10 bar, and the watch has a screw-down crown and a see-through screw case back. The official SLGC001 page lists the current model specifications.
Mt. Iwate dial and counter layout
The blue dial carries Grand Seiko’s Mt. Iwate pattern, inspired by the mountain’s ridged contours visible from the Shizukuishi studio. The chronograph counters are recessed, and the date sits between 4 and 5 o’clock. Grand Seiko says this arrangement preserves the hour indexes and supports legibility; its launch release describes the “intricately textured dial, prominent indexes, and recessed sub-dials” as adding depth and legibility. That is the maker’s design claim, not an independent legibility assessment.
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- Featuring a Black Band, Silver-tone Case, Scratch Resistant Hardlex Crystal
- Box-shaped Hardlex crystal
- Second hand halt mechanism (Hacking)
The watch also has a tachymeter and LumiBrite on the hands and indexes, according to Grand Seiko’s model specifications. Its dimensions and 154 g listed weight are useful considerations for fit, particularly for anyone who prefers a smaller or thinner chronograph.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What makes the SLGC001 distinctive?
The model’s central technical combination is its 10-beat-per-second movement and the manufacturer-stated 72-hour reserve while timing. The layout adds both a 30-minute and a 12-hour counter, so it can display elapsed periods beyond the short intervals covered by a basic chronograph. Grand Seiko called it the 10-beat chronograph with the industry’s longest power reserve, attributing that ranking to its own research as of March 2023; it is a dated manufacturer claim, not a current independently verified ranking. For an informed comparison with another chronograph, check the movement frequency, reserve with the chronograph running, dimensions, weight, water resistance, counter layout, accuracy context, and local price rather than relying on a single headline specification.
Price and availability
Price and availability depend on market and date. Grand Seiko’s March 2023 Canadian launch release listed a recommended retail price of CAD 18,500; that is a historical Canadian figure, not a current global price. The release identified Grand Seiko boutiques and select retail partners as sales channels at launch. For a present-day price or stock status, check a local authorized retailer or Grand Seiko’s regional product information rather than treating the launch price as current.
Grand Seiko’s launch details and design description are in its March 27, 2023 announcement. The movement’s lineage and named chronograph mechanisms are also discussed in the brand’s 9S anniversary chapter.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
