Learn more about Caliber 9S
The Shizukuishi Watch Studio
In 2004, to accommodate the long term development of Grand Seiko’s mechanical watches, a studio dedicated to the fully integrated production of high quality mechanical wristwatches opened in Shizukuishi, a town on the outskirts of Morioka, Iwate Prefecture. The studio is part of Seiko Instruments, whose origins stretch back to the foundation of Seikosha in 1892 from which Daini Seikosha (which is now Seiko Instruments) was spun off in 1937. At the Shizukuishi Watch Studio are teams of engineers and craftsmen, each specializing in the many disciplines that comprise the work of a true watchmaking manufacture. The studio is also its own academy; through a multi-tiered training system, the skills of watchmaking are handed down from one generation to the next and are honed in line with each advance in manufacturing.
An artisanal skill called “truing”
When a hairspring, finer than an actual strand of hair, is attached to a small metal wheel, the balance wheel is complete. With the expansion and contraction of the balance spring, the balance wheel rotates left and right like a pendulum. It is the precision of this oscillation that determines the accuracy of the watch. Truing is the expert craft of adjusting the balance spring so that it oscillates perfectly. Through a microscope, the craftsman observes the behavior of the balance wheel while it is moving and identifies even the slightest wobble. Pincers are then inserted into spaces 0.1 millimeter or smaller, between the rings of the spring, and adjustment to a precision of one hundredth of a millimeter are made to adjust the balance spring until it revolves perfectly and looks like a ripple spreading over still waters. Where should the tips of the pincers be inserted? How much force should be exerted? This is the real art of the craftsmen and women in the Shizukuishi Watch Studio; only they know the answers.
A new caliber for Grand Seiko’s women’s watches
In the Spring of 2018, the Shizukuishi Watch Studio gave birth to a new mechanical movement, Caliber 9S25. While many enhancements to existing calibers for women had been made down the years, this was the first completely new Grand Seiko women’s mechanical movement in 50 years. In the interests of slimness, its parts are necessarily up to 30 percent smaller than those of other 9S movements and yet the 8-beat Caliber 9S25 delivers a static accuracy of +8 to -3 seconds per day and a power reserve of more than 50 hours. Inside and out, the attention to design is uncompromising, even in components that are hidden from the eyes of the owner. For example, the escape wheel is delicately shaped like a five-petal flower and yet is hardly visible. Beauty is more than skin deep.