Grand Seiko Hi Beat 5646 8000 1970sMost of the 56GS production process was automated beginning in the 1970s. The precision level suffered as a result of this transition, with a decrease in movement speed from 36,000 bph to 28,800 bph. 5646 8000 is the Day date model with pillowcase style, 35mm diameter. The bezel and the sides of the case are polished but the lug sides of the pillowcase have a brushed finish. The watch is a very good condition. The crystal has slight marks but does not