Manual-winding Spring Drive
A manual-winding Spring Drive caliber made in the Shinshu Watch Studio, 9R31 has an innovative dual-spring barrel that contains two mainsprings set in parallel and delivers a power reserve of 72 hours.
|Winding mechanism||Manual winding|
|Accuracy||±15 seconds per month(±1 second per day)|
|Power reserve||Approximately 72 hours|
|Number of jewels||30 jewels|
-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.
Caliber 9R31 Models
9R Spring Drive Movement
The three movements at the heart of Grand Seiko
One of the world's foremost mechanical movements, the culmination of high-precision micro-engineering and the attention to detail of Seiko's expert watchmakers.
Spring Drive is a unique movement that delivers one-second-a-day precision, using just the power of a mainspring.