Released in 1975, the Cal. 5631 with design code 973 was part of Seiko's domestic market collection. Powered by the 5631 caliber with 22j jewels beating at 28,800 bph, it delivers a 48 hours power reserve. [seikata-wm-d7e8617a8e4b]
Also known as: Samurai, Golden Tuna
