Celebrating its 60th anniversary in 2020, Grand Seiko unveiled a new high frequency mechanical movement, Caliber 9SA5. Developed from the ground up after 9 years of development led by movement designer Hisashi Fujieda, 9SA5 is a 10-beat movement boasting 80 hours of power reserve and a precision rate of +5 to -3 seconds a day. Deploying all the skills and experience gained over the past six decades, Grand Seiko achieved in creating what is beyond doubt the finest mechanical caliber in its repertoire.
The precision, power, and slimness of Caliber 9SA5 are the result of the radical re-design of three key structures (and some components inside them), for which several patents are either already granted or pending. 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 increase in efficiency. It is unique in that in one direction power is transmitted directly to the balance, while in the other it is transmitted via the pallet fork, which is how it's done in a traditional escapement. Both pallet fork and escapement wheel are made using MEMS technology. 9SA5 also 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. The new caliber is also 15% slimmer than past Grand Seiko high frequency calibers, which is made possible via 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 that runs near the studio where the watch is made. Just as Caliber 9SA5 makes a significant and defining statement about the next stage of Grand Seiko’s technical development, the design also has a distinctive look that marks a new beginning.
SLGH002, a limited edition of just 100 pieces, is the first watch to house this new movement. Rendered in 18k yellow gold, the new intricate case design (inspired by the historical 44GS design) is beautifully finished, with stunning contrast between polished and brushed surfaces, of which there are many. The dial features new ornate hands and indexes, arguably the most complex Grand Seiko has ever produced. But despite their obvious beauty, they also serve a practical purpose. They pop against the base of the dial, making them incredibly easy to read. SLGH002 also has a crown that is positioned lower in the case. The effect is a watch that is ultimately thinner and one that has a lower center of gravity, which means that it will sit more securely against the wrist.