Grand Seiko · 9R Spring Drive
9RA2
A five-day Spring Drive calibre: mainspring power with quartz-referenced regulation.
At a glance
- Type
- Spring Drive
- Display / complication
- Date
- Architecture
- Dual barrels, Offset Magic Lever, electronic regulation
- Timebase
- Quartz-regulated glide
- Power reserve
- Approx. 120 h
- Jewels
- 38
Reference sources reviewed 7 November 2026. Published specifications, not independent measurements. Versions and complete-watch specifications can differ; fields without a verified figure are omitted or identified.
What distinguishes it
Look beyond the reference.
The mainspring powers the watch while a quartz reference and electronic control regulate the glide wheel. There is no balance beat rate to compare directly with a 3 or 5 Hz mechanical movement.
For the enthusiast
The power-reserve indicator sits on the movement side. Spring Drive is a distinct architecture: mainspring energy does not imply a conventional mechanical escapement.