The Grand Seiko SLGC001 Tentagraph is the Evolution 9 Collection’s first mechanical chronograph. Its new-for-Grand Seiko Caliber 9SC5 brings a 10-beat-per-second chronograph and an approximately 72-hour power reserve, while the watch pairs that movement with a substantial high-intensity titanium case and bracelet, ceramic bezel, and sport-focused dial. Grand Seiko lists the model at 43.2 mm across and 15.3 mm thick, so the specifications point to a capable but physically large watch.
What is the Grand Seiko Tentagraph?
The SLGC001 is an automatic mechanical chronograph in Grand Seiko’s Evolution 9 Collection. Grand Seiko identifies it as the brand’s first mechanical chronograph. Its Caliber 9SC5 is derived from the 9SA5, the brand’s high-beat automatic base movement. The result is a chronograph built around the Evolution 9 range’s sport-oriented case and legibility choices, rather than a new watch collection detached from that design language. Grand Seiko’s SLGC001 product page and its US boutique product page describe the watch and its specifications.
What does Tentagraph mean?
Grand Seiko forms the name from four specifications: “TEN” for ten beats per second, “Three” for the power reserve measured in days, “Automatic” for the winding system, and “chronoGRAPH” for the chronograph. Caliber 9SC5 runs at 36,000 vibrations per hour, or ten beats per second, and has an approximately 72-hour reserve. Grand Seiko says the reserve remains approximately 72 hours even while the chronograph is running. The brand’s 9SC5 instruction and specification sheet lists the frequency, automatic and manual winding, 60 jewels, and reserve.
How does the chronograph work, and what does the dial show?
The movement uses a column wheel and vertical clutch, according to Time+Tide’s hands-on review. Monochrome describes the chronograph as a module added to the 9SA5 base movement. That architecture is a design choice with trade-offs; neither modular nor integrated construction is automatically superior. For the wearer, the practical points are the chronograph display and the resulting watch dimensions. The available sources do not isolate how much thickness the chronograph module adds.
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#1 Best Overall
- See-through case back
- Date display
- Screw-down crown
- 40mm Diameter
- Weight 178.0 g
The display comprises central chronograph seconds, a 30-minute counter, a 12-hour counter, running seconds, and a date. Grand Seiko places the counters in recessed sub-dials below the main time display, and locates the date between four and five o’clock. The company says this date position preserves a marker at each traditional hour position. The blue dial is inspired by Mt. Iwate, while the recessed counters distinguish elapsed-time information from the main time display.
How big is the SLGC001?
Grand Seiko’s Benelux product page lists a 43.2 mm diameter, 51.5 mm lug-to-lug length, 15.3 mm thickness, 23 mm band width, and 154 g weight. Lug-to-lug length gives a better sense of how far the watch spans across a wrist than diameter alone; the 15.3 mm thickness may also affect how it sits beneath a cuff.
| Specification | Grand Seiko listing |
|---|---|
| Diameter | 43.2 mm |
| Lug-to-lug | 51.5 mm |
| Thickness | 15.3 mm |
| Band width | 23 mm |
| Weight | 154 g |
The 23 mm band width is from Grand Seiko’s current regional product specification. Monochrome’s 2023 launch article lists 22 mm instead; anyone sourcing a replacement strap should verify fit against the watch and its hardware rather than treating a 22 mm strap as confirmed compatible.
Rank #2
- Featuring a Black Band, Silver-tone Case, Scratch Resistant Hardlex Crystal
- Box-shaped Hardlex crystal
- Second hand halt mechanism (Hacking)
In Time+Tide’s cited hands-on review, the reviewer called the watch large for their taste but said it remained manageable on a 6.5-inch wrist, partly crediting the case’s cambered shape. That is one reviewer’s wearing impression, not a fit guarantee for other wrists.
What are the case materials and durability specifications?
The case and bracelet are made from high-intensity titanium, and the bezel is ceramic. Grand Seiko says its high-intensity titanium is about 30 percent lighter than stainless steel; that is the manufacturer’s comparison, not an independent measurement in the cited sources. The regional product page specifies 10-bar water resistance and magnetic resistance of 4,800 A/m. These are published specifications, not a claim that the watch is suitable for every water or magnetic exposure.
How accurate is Caliber 9SC5?
Grand Seiko publishes two accuracy figures with different conditions. Its mean daily rate is +5 to -3 seconds per day under controlled testing; its stated accuracy for normal use is +8 to -1 seconds per day. These should not be combined into a single range: the controlled test figure and the normal-use figure describe different contexts. The figures appear on Grand Seiko’s regional product page.
Rank #3
- STUNNING BLUE DIAL: this automatic men's watch features a deep blue, pressed pattern and gloss finish surrounded by a stainless steel watch case
- AUTOMATIC: these self-winding, automatic men's watches are powered by your movement, with a power reserve of 41 hours
- STAINLESS STEEL: features a durable stainless steel watch case and bracelet with see through caseback
- WATER-RESISTANT: these men's wrist watches are water-resistant down to 50 meters
- 4R35 CALIBER: equipped with the reliable caliber 4R35 automatic movement, this accurate men's watch keeps precise time
What does the Tentagraph cost?
Grand Seiko’s Benelux product page displayed a price of €15,000 when accessed in 2026. That is a region-specific listing and may change; check a local Grand Seiko boutique or salon for current price and availability. For historical context only, Time+Tide reported 2023 launch pricing of US$13,700 in the United States and A$20,500 in Australia, while Monochrome reported a 2023 launch price of €14,300. Those launch figures are not current-price quotes.
Why it matters in Evolution 9
The Tentagraph’s significance is specific: it brings Grand Seiko’s first mechanical chronograph into the Evolution 9 Collection, using a 9SA5-derived movement that runs at ten beats per second and retains an approximately three-day reserve with the chronograph operating. The collection’s sporty execution is equally concrete: titanium construction, a ceramic bezel, recessed counters, and a case with substantial height and span. Grand Seiko called it the industry’s longest-reserve 10-beat-per-second chronograph based on its research in March 2023; that dated manufacturer superlative is not independently established as current.
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