toki no waza The Artisan of Time

【Grand Seiko Assembly and Adjustment Technical Expert】

The 9S85 Self-Winding 10 Beat Movement

The heart of the mechanical watch is its movement. A "10-beat" movement means that the balance, the most important component for determining the accuracy of a watch, vibrates at 10 beats, or oscillations, per second. Mechanical watches, even luxury watches, operate at 5 to 8 beats per second. A higher number of vibrations makes a watch more resistant to shock, controlling fluctuations in dynamic accuracy—the watch's accuracy while being worn—to keep the time correctly and with stability. Seiko has succeeded in producing the Grand Seiko with a 10-beat movement, caliber 9S85. The watch is highly resistant to disturbance with minimized accuracy fluctuation when worn.

With the watch beating 10 times per second, the watch parts will come into more frequent contact, so they need to be made with higher durability. The 9S85 is made with parts manufactured using leading-edge technologies. They include a uniquely developed balance spring, an escape wheel and pallet made with micro-electro-mechanical systems (MEMS) technology, plus a laser displacement meter to check the weighting of the balance wheel, which is the key part in producing balance.

The strict criteria of the Grand Seiko are even tighter than the standards for Swiss chronometers. To meet such strict requirements, our master watchmakers work with a keen eye and are capable of detecting differences down to the micron level—0.001 mm. They are also able to make fine adjustments with incredibly steady fingers that beat out high-tech machinery every time. The 9S85 has high accuracy and reliability, perhaps the ultimate in a watch, and is finished beautifully, with fine craftsmanship. It is the pinnacle of manufacture d'horlogerie, the crystallization of all of Seiko's expert craftsmanship and cutting-edge technologies.

What is MEMS?

MEMS is an abbreviation for micro-electro-mechanical systems—a state-of-the-art processing technology used to manufacture semiconductors and other high-precision components. MEMS differs from the old metal processing methods of pressing, cutting, and polishing. Instead, shapes are made using photolithography (a process similar to developing photos using light-sensitive chemicals), on top of which a thick plating is deposited using electroforming technology. This processing method allows the manufacturing of complex shapes with greater accuracy than cutting, and also produces smoothly finished surfaces. In addition, hard materials can be used for parts while slightly adjusting the shape to keep the weight down, thereby greatly improving the accuracy and durability of the watch parts.