Cal. 9SA5 is the first movement in the new Hi-Beat 80 Hours 9SA series from Grand Seiko. It is a slim but oversized automatic movement with date. Cal. 9SA5 was introduced in 2020 in the Grand Seiko 60th Anniversary, Ref. SLGH002.
Seiko 9SA Family
The 9SA family movements operate at 36,000 A/h (10 Hz) yet achieve 80 hours power reserve thanks to precision materials and a novel double-impulse escapement. This escapement, similar to George Daniels famed Coaxial design, is paired with a free-sprung balance, a first for Grand Seiko. The movement wheel train is entirely new as well, designed so all of the gears sit are in a single plane, reducing movement thickness. This is possible thanks to a larger 31.86 mm diameter, up from 28.40 mm in previous Grand Seiko movements.