Despite the cancellation of Grand Seiko’s highest point, the new watches are being introduced anyway (credit for that). Subsequently, we’re kicking off with the new Grand Seiko 60th Anniversary Professional Diver’s 600M.

That’s right, Grand Seiko was brought into the world in 1960 and celebrates its 60th anniversary this year. Not exactly the celebration they had as a top priority in Japan, yet I am certain we will get a chance to see the watches live and to test drive them. For the present, we’ll have to make do with the public statements they’ve shared with us.

Grand Seiko 60th Anniversary Limited Edition Diver’s 600M

This watch may look familiar to you. It appears to be similar to the Grand Seiko Diver SBGA231G ( that I investigated here ) or perhaps better said, to the SBGH255 and SBGH257. While the SBGA231G is a digit smaller (and “only” water-resistant to 200 meters), it has a Spring Drive development inside. The SBGH255 has a couple of more similarities to this new 60th Anniversary Limited Edition Diver’s 600M. It is somewhat larger with its 46.9mm High-Intensity Titanium case, and it has a Hi-beat development. A picture of the SBGH257 from 2017 can be found below.

Grand Seiko Hi-Beat 36000 Professional 600m Diver SBGH257

A few more differences

Although the new Grand Seiko Diver (SLGA001) watch looks very much like the 2017 models (like the above), there are — other than the dial — a couple of more differences of course. For starters, the new Grand Seiko 60th Anniversary Limited Edition Professional Diver’s 600M features the brand new Spring Drive caliber 9RA5 development. This newcomer boasts an incredible 120 hours power hold. This liberal run time is courtesy of a dual-barrel framework. Unusually, the barrels are of various sizes. This enables them to generate the necessary force while remaining compact enough to fit inside this new, slimline Spring Drive caliber.

Spring Drive Caliber 9RA5

But it is something beyond more force hold. To celebrate its 60th anniversary, Grand Seiko built up this new development to become slimmer and more accurate than the other Spring Drive developments. Its month to month precision rate has improved from ±15 seconds a month to ±10 (and ±0.5 each day). The thickness of the development has been reduced from 5.8mm to 5.0mm and the speed of the date change increased.

The reduction in thickness of the development also brings about a thinner watch (than the 17mm SBGH255 and SBGH257 for example). This new Grand Seiko Diver reference SLGA001 has a thickness of 16mm. Alright, that’s still not a thin watch. In any case, considering the 600m profundity rating, that’s pretty noteworthy. I’m sure we’ll locate this one on the wrist of many a saturation diver, who are regularly needed to work at such depths.

Grand Seiko’s development planners reduced the size by repositioning the Magic Lever construction. (Grand) Seiko has been utilizing the Magic Lever since 1959 and it is a clever framework that supports the efficiency of oneself twisting mechanism by utilizing the energy created by the bi-directional twisting of the rotor.  For the Grand Seiko caliber 9RA5, the (Offset) Magic Lever isn’t situated in the center anymore, as the new name suggests. This assists with reducing the thickness of the development. Additionally, the winding efficiency remains unaffected by this new configuration.

Shock resistance

But wait, there are more 60th anniversary treats available. Regardless of the slimness of this development, Grand Seiko enhanced the shock resistance of it by adopting another gear train layout. A central extension (One-Piece Center Bridge) holds them all together, making it more inflexible and achieving a shock resistance that fulfills the ISO guideline for divers’ watches. Grand Seiko shared a drawing with us on what this new construction looks like.

Last however not least, Grand Seiko upgraded the IC. It is currently outfitted with a sensor to measure the temperature changes inside the development and compensate for any inaccuracies because of these in the oscillation rate. Both the oscillator and sensor are vacuum-sealed into one package, to reduce conceivable external influences. Everything is done to maintain the highest conceivable accuracy of the development, and the outcomes are very amazing (+/ – 0.5 seconds per day).


As you can read, the SLGA001 is an extremely technical watch, hi-tech, I’d say. The Spring Drive caliber 9RA5 development as well as the utilization of the brand’s high-power titanium for the case and bracelet. This material is 40% lighter than stainless steel. It is also more resistant to scratches, which some way or another always look more regrettable on titanium than on steel. At least that’s from my own experience of wearing titanium watches. The case construction is helium without valve for use by saturation divers, and the high-definition sapphire crystal guarantees clear vision on the dial under almost all circumstances.

The finish working on it, bracelet, dial, hands, etcetera is as great as we’ve come to expect from Grand Seiko. There’s a reason we’ve been raving about taking all things together these years. It’s basically dazzling. There will be just 700 of these Grand Seiko 60th Anniversary restricted version Diver’s 600M watches. It retails for €11,500 including VAT. It will be conveyed in a Grand Seiko 60th Anniversary box and includes an additional blue silicone strap. We can’t wait to go hands-on with this new Grand Seiko reference. And since it is the 60th anniversary, there are loads more releases to come! Stay tuned. More information via Grand Seiko .