Manual-winding Spring Drive

Calibre 9R31

A manual-winding Spring Drive from Shinshu Watch Studio with the same concept as Calibre 9R02.

Created at the same time as Calibre 9R02 from Micro Artist Studio, Calibre 9R31 has Dual-Spring Barrel with two mainsprings set in parallel within a single barrel, to deliver a power reserve of 72 hours.

Specifications

Winding mechanism Manual winding
Accuracy ±15 seconds per month(±1 second per day)
Power reserve Approximately 72 hours
Number of jewels 30 jewels
Features -Dual-Spring Barrel
-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.

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