The 9S family of high-end watch movements is the flagship mechanical watch product of Seiko. It includes the initial 9S5x range along with the less-decorated and unadjusted 8L family, the Hi-Beat 9S8x family, and the “3 Days” power reserve 9S6x movements.
The 8L/9S family is intended to compete with limited-production Swiss movements from companies like Rolex. Most are automatic, unlike the ultra-thin Seiko 6800 family, though there are manually-wound versions. The 9S family are carefully finished with Tokyo Stripes and rhodium plating and are adjusted to six positions, while the 8L family has a brushed and gilt finish, with colimaconnage on the rotor and is unadjusted. “9S” models are only used in Grand Seiko watches, while “8L” models are used in other ranges.
The 9S family includes many notable Seiko movements
The Calibre 8L and 9S families are assembled at Seiko's Shizukuishi Watch Studio in Morioka, Iwate prefecture, Japan, along with other high-end Seiko movements.