Hi-Beat 36000 80 Hours Caliber 9SA5

The Hi-beat 36000 80 Hours watch offers a new perspective on the nature of time. Its dial is inspired by the slender and strikingly beautiful white birch tree forests that thrive in northern parts of Japan, and that grow in profusion near the Grand Seiko Studio Shizukuishi where this and all Grand Seiko mechanical watches are made. The intricate texture, fine detail and delicate subtlety of the watch opens onto the distinctive natural environment of Japan and the exquisite craftsmanship of Grand Seiko.

The watch is powered by the revolutionary Caliber 9SA5, released in 2020 in celebration of the 60th anniversary of Grand Seiko. The SLGH005 watch is the first creation equipped with the new caliber to join the main Grand Seiko collection. Caliber 9SA5 has a precision rate of -3 to +5 seconds a day and achieves a long power reserve of 80 hours. The precision, power and slimness of Caliber 9SA5 are the result of the radical re-design of key structures.

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. 

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 allows for its isochronism to be adjusted. 

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 watches powerful hands and grooved, prominent markers ensure perfect legibility and its Zaratsu polished, distortion-free mirror finish and delicate hairline finish alternate to give the case a quiet and harmonious glow. The case has wide lugs and a low center of gravity that ensure that the watch sits easily and securely on the wrist. The design is true to the Grand Seiko Style defined back in 1967 with the celebrated 44GS, but its heritage is combined with a powerful contemporary feel that points towards a new era.