Introducing The Grand Seiko 60th Anniversary Limited Edition Professional Diver’s 600M SLGA001, With New Spring Drive Caliber 9RA5
Spring Drive technology from Seiko has had a long and now and again arduous history. The technical story starts in the late 1970s, when Yoshikazu Akahane came up with the original idea, and when the primary Spring Drive was released in 1999, the development exertion had produced more than 200 patents and many hundreds of models. The primary automatic Spring Drive developments came out in 2005 and since at that point, Spring Drive has appeared in everything from chronographs, to dive watches, to amazingly elevated chiming complications. It has also appeared a lot of dressed for the ball, in Credor and all the more recently, Grand Seiko watches. For sheer diversity of articulation, it is equaled by not many other movements.
Grand Seiko has quite recently announced the following stage in the development of Spring Drive technology: the new caliber 9RA5. It is by all accounts a touch of topic this year for performance upgrades launching in Grand Seiko watches, as we’ve recently seen with the new Hi-Beat limited edition, with the caliber 9SA5. 9SA5 is a more slender variant of the Grand Seiko Hi-Beat, with a 80-hour power hold, and the new caliber 9RA5 in like manner offers an extended force save of as long as 5 days, or 120 hours – in a development 0.8mm more slender than the current 9R65 caliber and which is all the more firmly regulated as well. The launch platform for the new development is another diver’s watch, with a 600 water-resistant “focused energy titanium” case: the SLGA001 Professional Diver’s 600M.
This will be the deepest-diving Spring Drive Pro Diver from Grand Seiko – the two current Spring Drive dive watches, SBGA231 and SBGA229 , are both rated to 200 meters, with the 600 meter rating reserved for the mechanical SBGH255 , which also has a delicate iron dial and is antimagnetic to 16,000 A/m. Spring Drive is in many respects an ideal technology for a dive watch – you have quartz watch accuracy, without dependence on batteries (it’s always worth recollecting that Spring Drive watches are powered by a mainspring). The new SLGA001 is, not unexpectedly, a stout creature of the deep, at 46.9mm x 16.0mm, however the utilization of titanium for the case and bracelet should do much to reduce the perceived bulk. Professional dive watches from Seiko generally avoid helium release valves – instead the seals and gaskets are designed to forestall helium gas interruption in any case, which is valid for the new SLGA001 as well. This makes the watch suitable for use by professional saturation divers.
The new caliber 9RA5 incorporates various enhancements to oneself winding Spring Drive developments. It is by all accounts an objective for Grand Seiko to have the potential to produce more slender watches, and while the SLGA001 is a thick watch, the caliber 9RA5 incorporates a few changes in construction to allow for a flatter profile.
The Magic Lever winding framework, appeared with the oscillating weight and the two mainspring barrels.
One of these, according to Grand Seiko, is a slight re-situating of the Magic Lever away from the center of the development, which allows it to sit flatter under the winding rotor. The Magic Lever framework is something of a signature feature of Seiko watches; it’s been around in some structure since 1959 and is a remarkably straightforward, vigorous mechanism.
The gear train has also had its layout tweaked and now lies along the central horizontal axis of the development under a one-piece central bridge. The outcome is more grounded construction and better resistance to shock.
The “One Piece Center Bridge” appeared in dark grey.
The longer force save is courtesy of two mainspring barrels which lie in the same plane in the development (again, this aides keep the development relatively flat). The two barrels are asymmetrical regarding size, which allows them to fit in the available space while as yet offering maximum bang for the buck as far as energy delivery.
The twin mainspring barrels.
Finally, the quartz timing package, which controls the rate of rotation of the Spring Drive glide wheel, presently features temperature compensation – again, according to Grand Seiko, this is a first for any Spring Drive development. Temperature compensation is via a thermal sensor, which is in the same hermetically sealed package as the quartz crystal, to guarantee the temp reading exactly matches the ambient temp affecting the crystal. Accuracy is improved to ±10 seconds of the month maximum deviation from rate, over ±15 seconds of the month for a standard Spring Drive caliber.
The new development is an intriguing development. As with Seiko developments in general, Spring Drive calibers have tended to be on the hearty side, with more idea given to reliability and sturdiness than to reducing stature. At 5.0mm thick we have, in the 9RA5, a Spring Drive caliber which approaches the stature of some classic simply mechanical workhorse developments. The ETA 2825, for instance, is 4.8mm thick, to pick only one example.
The SLGA001 is a limited edition of 700 pieces globally and the price, at $11,100, will take some becoming acclimated to, although there are arguments to be made for it, considering the technology and high caliber of construction. (The alleged High Intensity Titanium used for the case, for instance, is a proprietary alloy which is both harder and 30% lighter than standard stainless prepares, and it’s not surface hardened, which means the case can be refinished if necessary). As solidly as cheap and cheerful, no nonsense Seiko dive watches are entrenched in so many of our recollections, there’s no denying that SLGA001 isn’t your dad’s (or your) SKX007. Instead, it’s a precision-made piece of very good quality horological designing, designed to keep Grand Seiko’s apparatus watches at the cutting edge of horological innovation.
The Grand Seiko 60th Anniversary Limited Edition Professional Diver’s 600M SLGA001: Case, focused energy titanium, 46.9mm x 16.0mm, 600 meters water resistant; case is resistant to helium interruption, making it suitable for saturation diving; sapphire crystal. Development, Spring Drive 5 Day Caliber 9RA5, self-winding, with Magic Lever; 5 day power hold; 34.0mm x 5.0mm, running in 38 gems; accuracy ±10 seconds out of each month. Limited edition of 700 pieces world-wide; price, $11,100. Find out more at Grand-Seiko.com.