GRAND SEIKO SLGA001

About Grand Seiko SLGA001

Grand Seiko Sport Collection

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

Grand Seiko introduces a new generation Spring Drive caliber that is slimmer, even more precise and has a greater power reserve. Caliber 9RA5 takes Spring Drive technology to a new level of excellence and opens a new era in the history of Grand Seiko.
Caliber 9RA5’s thin profile is made possible by the re-design and re-positioning of the Magic Lever. In the new caliber, the new Offset Magic Lever is positioned away from the center of the movement to reduce its thickness. Remarkably, this is achieved with no loss of winding efficiency.
Caliber 9RA5 may be slim but it has enhanced rigidity and shock resistance thanks to the new layout of the gear train towards the center of the movement and a central bridge that holds them together. This One-piece Center Bridge achieves a shock resistance that meets the ISO standard for diver’s watches.
The movement incorporates two barrels which deliver a power reserve of up to 120 hours. They are different sizes so as to deliver the torque required for the five day power reserve while optimizing the use of the limited space within the movement.
Caliber 9RA5 has an accuracy rate of ±10 seconds per month thanks to a new IC package and to the selection of highly stable quartz oscillators that have gone through a three-month aging process.
The finishing of 9RA5, also, the movement has a beauty that is uniquely Japanese and is inspired by the natural environment of the studio where it is made. The jewels echo the glittering stars that sparkle especially brightly during the early days of winter in the surrounding mountains and the delicate texture of the movement’s surfaces reflect the frost that winter brings to the trees.
The case is in high-intensity titanium, which is 40% lighter than steel and more impervious to scratches. The power reserve is at the 10 o’clock position and the indicator is divided into five parts to show exactly and clearly how many days of power are left. The case, crystal and bezel are all designed for easy and safe disassembly for the maintenance that a professional diver demands. It is a watch entirely worthy of the high performance of the new caliber that powers it.
The dial color is Grand Seiko blue, a special color that symbolizes the brand. It is a special specification unique to limited edition.
The watch is presented in a special Grand Seiko 60th anniversary box with an interchangeable blue silicone strap.

It will be available worldwide in August 2020 as a Limited Edition of 700 pieces.

About Spring Drive

Spring Drive is Seiko’s exclusive movement that achieves an unprecedented level of accuracy (+/- 15 seconds per month on average, equivalent to +/- 1 second per day) by regulating a spring-driven watch with state-of-the-art electronic technology that functions without batteries or other external power source.

As in conventional mechanical watches, the sole power source of Spring Drive is a mainspring that can be wound by the motion of an oscillating weight or by winding the crown. And just as in mechanical watches, the mainspring drives a series of gears that rotate the hour, minute and second hands. A rotor, connected to the end of these gears, generate a small electrical charge that activates an electronic circuit and quartz oscillator.

The Tri-synchro regulator is a unique speed controller for Spring Drive that replaces the escapement, which is a mechanical speed control device used in almost all conventional mechanical watches. The Tri-synchro regulator moves the second hand in a smooth motion, without ticking and with extreme accuracy.

Some 80% of the components in a Spring Drive caliber are the same as those in a luxury mechanical watch. Spring Drive is a movement powered by a spring, just like a mechanical watch, with a different kind of regulator and combines the long-lasting autonomy of a mechanical watch with the precision that, until now, only electronic watches could provide.

To ensure reliable and accurate operation, all these parts need to be manufactured to the highest standards of precision, and assembling them requires superior craftsmanship.

The development of the Spring Drive movement caliber 9R was made possible because Seiko is one of the very few manufactures with expertise in both mechanical and quartz watches.

Since the first Grand Seiko Spring Drive in 2004, new movements have been created with even more complex mechanisms–including the GMT in 2005 and chronograph with GMT in 2007. Showing that with the Spring Drive caliber 9R, time never loses momentum.