HANDS-ON: The Grand Seiko SLGC001 Tentagraph puts the evolution in Evolution 9
Zach BlassGrand Seiko is well-known for a wide array of dial expressions, faceted case geometries, handsome Zaratsu finishing, and, of course, their proprietary Spring Drive system. But as one of few truly vertically integrated manufactures, Grand Seiko does have one glaring gap in their catalogue: complications. Yes, Grand Seiko has previously presented GMT watches and even chronograph GMT watches. But, the chronograph GMT watches are Spring Drive-powered, and when you look to other higher complications, such as the perpetual calendar, it was not until last year’s SLGT003 Kodo Constant-Force Tourbillon that they had even entered the hi-comp arena. Day-dates and world timers are both uncovered ground for the brand, offering tantalising future possibilities. But at Watches & Wonders 2023, it was exciting to see Grand Seiko present their first-ever fully mechanical chronograph watch: the Grand Seiko SLGC001 Tentagraph. The SLGC001 really puts the “evolution” in Evolution 9 with a first-ever not just for the collection, but for the brand as a whole.
The movement
As expected from Grand Seiko, the Tentagraph name is very intentional and precise: TEN beats per second, Three days, Automatic chronoGRAPH. The calibre, dubbed the 9SC5, is built upon their game-changing latest-gen hi-beat calibre 9SA5 which notably boasts 80 hours of power reserve, a Grand Seiko overcoil hairspring, and a dual-impulse escapement. When adapting the 9SA5 into a chronograph calibre, Grand Seiko had to ensure the movement, with the added complication, would still adhere to the Grand Seiko standard – a component of which is a minimum three days of power reserve. Due to the energy efficiency of the calibre, the 9SC5 has eight hours less power reserve than the 9SA5 – which totals exactly 72 hours down from 80.
Looking at the 9SC5 calibre, you would be forgiven for thinking it was the 9SA5 as the front of the calibre is effectively identical in aesthetic with its full balance bridge and diamond-cut bridges inspired by the river Shizukuishi. That being said, the addition of a modular chronograph means new components and architectures have entered the mix. Based on the position of the registers and date window on the dial, some have suggested there is a strong connection between the Seiko NE88 movement and new Grand Seiko 9SC5 movement. But, according to Grand Seiko, the chronograph module used in the 9SC5 is exclusive to Grand Seiko.
The 9SC5 is a hi-beat automatic vertical-clutch column wheel chronograph movement, which means the pusher actuation will be butter-smooth, the chronograph seconds hand will have no stutter upon its start, and can be run continuously with minimal wear to the movement. Furthermore, Grand Seiko pledges its 72 hour power reserve is inclusive of the chronograph continuously running and the calibre, in accordance with the Grand Seiko standard, is regulated in six positions at three temperatures and assessed over 17 days to run within +5/-3 seconds per day.
The case
Of course, while the movement is a fascinating development, the case it is situated within is equally important to the offering. For this first Tentagraph entry, the Grand Seiko SLGC001 is cased in the manufacture’s high-intensity titanium and in the highly faceted Evolution 9 case design. It certainly skews on the larger side, with a diameter of 43.2mm and a case thickness of 15.3mm and, like the Evolution 9 diver SLGA015, spans 51.5mm lug-to-lug across the wrist. Not an ideal size for me personally, but, even on my smaller 6.5 inch wrist, I felt I could get away with it due to the banana cambering of the case. The benefit of its size, hi-intensity titanium case and bracelet, and ceramic bezel, is that it is certainly highly robust and scratch-resistant as a result – especially with its screw-down crown secured 100-metre depth rating.
It is also worth noting that part of the reason the watch is thicker and wider is due to the fact the 9SC5 is a modular chronograph calibre (adding height), and that Grand Seiko’s perfectionism led them to design the pushers, in spite of the modular movement, in perfect alignment with the crown (the system making this possible adding a tad more width in diameter).
The dial
Underneath the boxed and AR-coated sapphire crystal, and framed within the black ceramic tachymeter bezel, the blue dial primarily features Grand Seiko’s signature Mt. Iwate pattern and texture with the exception of the three recessed and concentrically textured chronograph counters and the dial-matching white on blue date disc placed at the contentious 4:30 position. At 3′ you have a running seconds counter, at 6′ a 12-hour elapsed-hours counter, and at 9′ a 30-minute elapsed-minutes counter.
Grand Seiko, as expected for an Evolution 9 design has utilised the broader and partially lumed hours and minutes hands. The faceted, diamond-cut, applied hour indices also feature luminous channels, and the central running chronograph seconds hand has a long portion with a luminous coating as well. The small hands of the counters, however, do not leverage luminous coatings, so they will not be the most visible in darker conditions.
The bracelet
Also in expected Evolution 9 form, the Grand Seiko Tentagraph SLGC001 makes use of a wide high-intensity titanium bracelet with the five-piece link set fully hairline brushed on its top facet – with strictly the outer shoulders of the outer link pieces thinly mirror-bevelled. It is secured to the wrist via the familiar three-fold clasp with safety buttons.
The verdict
This is certainly a neat expansion of the Evolution 9 collection, their roster of in-house mechanical calibres, and their repertoire of complications. While I think this is a phenomenal first start, I would be interested to see if, like the 9SA5, the 33mm diameter and 8mm thick 9SC5 calibre ever makes its way into case geometries outside of Evolution 9 – perhaps in a dressier and more vintage-inspired package. I highly doubt it at this time. For now, Grand Seiko enthusiasts who like their sportier designs certainly have a strong offering to dive into. But, in a way, I am more intrigued by the doors the 9SC5 calibre could open than the destination we have currently arrived at.
Grand Seiko Tentagraph SLGC001 pricing and availability:
The Grand Seiko Tentagraph SLGC001 will be available for purchase via Grand Seiko boutiques and authorised dealers. Price: A$20,500 / US$13,700
| Brand | Grand Seiko |
| Model | SLGC001 ‘Tentagraph’ |
| Case Dimensions | 43.2mm (D) x 15.3mm (T) x 51.5mm (L2L) |
| Case Material | High-intensity titanium |
| Water Resistance | 100m (screw-down crown) |
| Dial | Blue Mt. Iwate dial |
| Crystal | Sapphire crystal and caseback |
| Bracelet/Strap | High-intensity titanium bracelet, three-fold clasp with push button release |
| Movement | In-house automatic hi-beat 9SC5 |
| Power Reserve | 72 hours |
| Functions | Hours, minutes, running seconds, chronograph, date |
| Availability | Availble now for pre-order, ships June 2023 |
| Price | A$20,500 / US$13,700 |