Automatic Spring Drive 3-Day
Calibre 9R15
Calibre 9R15 is specially adjusted Calibre 9R65, to deliver an even higher level of precision.
Calibre 9R65 is ±15 seconds a month (equivalent to ±1 second per day), whereas Calibre 9R15 is ±10 seconds a month (equivalent to ±0.5 seconds per day).
The difference between the two movements lies in the quartz crystal oscillator, which delivers accurate electrical signals.
All 9R Spring Drive use quartz crystal oscillator with stable accuracy. Among them, only quartz crystal oscillator, which exhibit particularly excellent performance, are selected and mounted on the Calibre 9R15.
The Grand Seiko lion in 18K gold graces the oscillating weight to symbolize the enhanced accuracy.
Specifications
| Winding mechanism | Automatic with manual winding |
|---|---|
| Accuracy | ±0.5 second per day (±10 seconds per month) |
| Power reserve | Approximately 72 hours |
| Number of jewels | 30 jewels |
| Features | -Power reserve indicator |
What makes 9R Spring Drive special?
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.
