Grand Seiko caliber 9R65
Caliber 9R65 is a self-winding movement based on Seiko's Spring Drive technology. It is currently the most standard of the 9R Spring Drive movements, and is used in many Grand Seiko models.
Spring Drive, one of the great innovations in modern watch making history, regulates a spring-driven movement with state-of-the-art electronic technology that functions without batteries or other external power source. Its sole power source is a mainspring, which drives a series of gears. A rotor, connected to the end of these gears, generates a small electrical charge that activates an electronic circuit and quartz oscillator. Its accuracy is unprecedented for a watch wound by a mainspring. The development of the 9R Spring Drive movement was possible only because Grand Seiko is one of the few manufacturers with expertise in both mechanical and electronic watches.