Grand Seiko’s New Tentagraph (Unbelievably) Is The Brand’s First Mechanical Chronograph

by Matt Clymo

If you thought Grand Seiko has had mechanical chronographs for long time, you wouldn’t be alone. This year, the brand has released its very first mechanical automatic chronograph – The Tentagraph, a chronograph with a 10 second hi-beat rate.

Whilst Grand Seiko have been making chronographs for quite sometime, up ’til now, they’ve all been powered by their famous Spring Drive Movement – a combination of quartz and mechanical fused together. The mechanical part of the movement provides the power to the quartz oscillator which then drives the movement with incredible accuracy, around half a second a day.

But first, lets get this out of the way. What exactly does Tentagraph mean? Well, the answer is simple. Its a kind of an acronym and stands for TEN beats per second, Three Days, Automatic ChronoGRAPH. TENTAGRAPH. Lets move on…

The new Grand Seiko Tentagraph with deep blue dial evoking the night sky above Mt Iwate.

The Grand Seiko Tentagraph however is a full automatic movement based on the revolutionary high-beat Calibre 9SA5. Like Calibre 9SA5, the new Tentagraph Calibre 9SC5 beats ten times per second, ensuring high accuracy when measuring elapsed time as well as the time of day. Grand Seiko, not one to do things by halves, has given the Tentagraph two barrels so the watch runs for three days even when the chronograph is in operation, making (according to Grand Seiko research) the Tentagraph the 10-beat chronograph with the longest power reserve in the industry today.

Grand Seiko also make sure that the Tentagraph is tested and running to their exacting standards. Over 20 days, GS tests the watch. Firstly it assesses it in six positions and at three temperatures over 17 days, then it tests over an additional 3 days whilst the chronograph is in operation. This ensures that the movement is accurate to -3/+5 seconds per day.

Grand Seiko Tentagraph Calibre 9SC5 beautifully finished

Whilst we’re nerding out on the movement, it would be wrong of us to leave out the next part. Grand Seiko have given the Tentagraph their new Dual Impulse Escapement, which efficiently transfers energy to the free-sprung balance wheel indirectly through the pallet fork and also directly from the escape wheel. This assists in generating greater efficiency, which in turn, gives the Calibre 9SC5 its long power reserve.

The Grand Seiko Tentagraph isn’t just about the movement however. They have produced an extremely good looking chronograph. The case and bracelet are made of high-intensity titanium, which is about 30% lighter and more scratch resistant than stainless steel to maximize durability. The case has a combination of brushed and polished surfaces, with lightly curving lugs that are built for comfort. The Zaratsu polishing on the bevelled edges and ends of the lugs and case gives the watch a more even flow and the shape is slightly reminiscent of the Chronomaster Sports case design.

The curved lugs and bevelled finishing on the case.

Like all modern Grand Seiko’s, the dial of the Tentagraph is a work of art, and takes inspiration from the surrounding world. The watch’s dial pattern evokes the magnificence of Mt. Iwate, the soaring peak visible from the Grand Seiko Studio Shizukuishi, where the Tentagraph and all other Grand Seiko mechanical watches are hand assembled and adjusted. The blue hue is meant to represent the night sky above Mt. Iwate, and encourages us to look upwards towards it and the peak. I think there is something in that evocative picture for all of us.

The deep blue textured dial of the Tentagraph with the exquisitely finished hands and indices

The Tentagraph has a more traditional curved box shaped crystal, which leads into the scratch proof ceramic bezel, complete with Tachymeter scale. This combined with the dial and redesigned indexes and hands, helps the Tentagraph to achieve maximum legibility, allowing the wearer to check the time with just a glance. Furthering this, Grand Seiko has designed the seconds hand of the chronograph and the minutes hand to gently curve at the ends, bringing them closer to the markers for even easier reading.

The ceramic bezel with Tachymeter scale surrounding the box style sapphire crystal and gently curving hands towards the dial

Final Thoughts

Grand Seiko has designed, crafted and made a nice looking chronograph with all the traditional hallmarks of a sports chronograph. Whilst this doesn’t look all that different on the surface to any other sports steel chronograph, dive a little deeper and it’s actually a lot more! The use of Titanium and ceramic sets this apart straight away, and as does Grand Seiko’s finishing on, well, everything. If you’ve ever looked at a Grand Seiko movement, or hands etc under a macro lens, you’ll know what I’m talking about. GS dials are just magical, and the Tentagraph’s is no different.

Then you get under the hood, and the Calibre 9SC5 is Grand Seiko engineering at its finest – and on its first ever automatic mechanical chronograph movement too. The one thing that gets me is the price. At AUD $20,500, it’s a lot. You get a lot of watch, but I can’t help feel its maybe a little overpriced. This is Daytona money here (assuming you pay and can get one at retail) or just shy of an Omega Speedmaster Moonphase Blue Side Of The Moon with Adventurine dial. However, the Tentagraph will fly under the radar, and should someone notice it an ask “Hey, nice watch, what is it?” You’ll most certainly have a talking point!

Reference: SLGC001


  • Case: 43.2mm diameter. 15.2mm Thick
  • Case Material: High-intensity titanium, screw down crown
  • Dial: Deep blue texture dial with 30-minute counter at 9 o’clock and 12-hour counter at 6 o’clock
  • Crystal: Box style Sapphire crystal with anti-reflective coating. See through case back
  • Bezel: Black ceramic with graduated Tachymeter scale
  • Movement: Calibre 9SC5 automatic chronograph. 36,000 vph / 5Hz (10 beats per second) and accurate to +5 / -3 seconds per day
  • Power reserve: 72 Hours with chronograph running
  • Water Resistance: 100m / 10bar
  • Bracelet: Titanium bracelet with three-fold clasp with push button release
  • Warranty: 5 years factory warranty 


AVAILABILITY: Available at Grand Seiko Boutiques & select retail partners starting in June 2023. Available for pre-order online at

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