Seiko 9R15

Caliber 9R15 is Seiko's in-house Spring Drive automatic movement, introduced in 2010 and remaining in production. It belongs to the 9R family of Spring Drive calibers, which use a quartz-regulated electromagnetic braking system to achieve the smooth, continuous sweep seconds hand characteristic of the technology. The 9R15 powers select Grand Seiko and Seiko models, representing Seiko's proprietary Spring Drive platform within its in-house movement portfolio.