Grand Seiko 9SA5 Hi-Beat 36000 80 Hours
9SA5 is an entirely new mechanical movement developed from scratch exclusively for Grand Seiko and will be the foundation upon which a whole new generation of Grand Seiko mechanical watches will be created. Nine years in development and deploying all the skills and experience that Grand Seiko has gained over the past 60 years, 9SA5 is no doubt the finest mechanical caliber the brand has ever created.
9SA5 has a precision rate of +5 to -3 seconds a day and a power reserve of 80 hours and yet is 15% slimmer than the current Grand Seiko high beat caliber. The precision, power and slimness of Caliber 9SA5 are the result of the radical re-design of three key structures and some components within them for which several patents are either already granted or pending.
1. Dual Impulse Escapement
The escapement is entirely new and was developed in-house. It enables the escapement wheel to transmit power directly to the balance, leading to an efficiency increase. It is unique in that, in one direction, power is transmitted directly to the balance while in the other it is via the pallet fork, as in a traditional escapement. Both pallet fork and escapement wheel are made using MEMS technology.
2. Grand Seiko Free-sprung Balance
9SA5 uses a new and special free-sprung balance developed for this caliber. It retains its precision for longer and is more resistant to shock and friction. While the current Caliber 9S uses a flat hairspring, 9SA5 uses an overcoil, whose curved shape was decided after more than 80,000 simulations with the result that its performance is optimized in every possible position. Its unique design improves the isochronism.
3. Horizontal Gear Train
The new caliber is 15% slimmer than the current Grand Seiko high beat caliber, thanks to the innovative horizontal layout of the barrel and gear trains.
The movement is as beautifully finished as it is efficient. The bridge has a gently curving outline that is inspired by the shapes of Mt. Iwate and a bend in the Shizukuishi River near the studio where the watch is made.
The design has a distinctive look that is true to the Grand Seiko Style that was defined back in 1967 with the celebrated 44GS but it is different in several ways. It has all the hallmarks of Grand Seiko but also offers enhanced comfort and legibility. The slimness of the caliber does much to ensure that the watch can sit easily but it is combined with slightly wider lugs so that the watch also stays more solidly on the wrist. The already high legibility of Grand Seiko is further enhanced by the increased volume of the hour hand and by the hour markers that are more prominent, just as they were in the first Grand Seiko of 1960. An 18k gold case watch with a new design is the first creation to be powered by this new caliber. The letters GS, indexes and calendar frame are also in 18k yellow gold.