Introduced in 2020, the Grand Seiko Caliber 9SA5 is their 80-hour, Hi-Beat 36000 (10 beat) movement, which aims to continue to push horological boundaries. With an average time deviation of +5/-3 seconds per day (COSC standards at +6/-4 seconds per day), this movement utilizes several revolutionary innovations to accomplish this. The dual impulse escapement, which regulates the release of energy in the movement, increases the transfer efficiency directly from the escape wheel to the balance wheel. Via the mainspring. The twin barrels also allow the 80-hour power-reserve despite the higher rate of beats (which consumes more energy). Additionally, the geniuses at Grand Seiko incorporated an overcoil (developed after more than 80,000 simulations) on the mainspring to deliver increased precision and stability. Moreover, the Grand Seiko watchmakers developed a free-spring balance wheel, which does away with a regulator (think Swiss-lever). Instead, this innovation uses four screws on the side of the balance wheel, which allows for fine tuning to make the watch faster or slower. Doing away with the regulator increases the longevity and durability of the hairspring as well as the precision.
With all these inventions and innovations, one might think the movement and watch would increase dramatically in size, however this movement is 15% (0.8mm) thinner than their other Hi-Beat 36000 movements. Not only slimmer but it is a beautiful movement, drawing from inspiration of Mt. Iwate (seen by the gentle curves on the bridge of the movement).
Originally introduced in the limited edition SLGH002 (100pieces in 18k yellow gold) and the SLGH003 (1,000 pieces for the 60th anniversary), the 9SA5 is now being regularly produced in the fantastically beautiful SLGH005. The SLGH005 captures the beautiful of the white birch forest near the studio in Shizukuishi where the movement is produced, as seen on its gorgeous texturized, white dial. The bracelet is studier in this model than other as well. 40mm by 11.7mm thick, 100M water resistant at a value of $9,100. Please contact Schwanke-Kasten Jewelers in Whitefish Bay, WI to express interest in this incredible Grand Seiko.