The Miyota 8215 is a Japanese mechanical movement powered by a mainspring. Wrist motion winds it automatically, and you can also wind it by hand. It brings mechanical watchmaking to an everyday three-hand watch with a date.
Specifications at a glance
| Manufacturer / caliber | Miyota / 8215 |
|---|---|
| Movement type | Mechanical automatic |
| Manufacturer / origin note | Japanese manufacturer; movement origin does not establish the origin of the complete watch |
| Functions | Hours, minutes, seconds, date with quick setting |
| Power source | Mainspring; automatic winding and hand winding |
| Hand winding | Yes |
| Stop-seconds (hacking) | Yes in Miyota’s current published specification; confirm the version fitted to a specific watch |
| Published accuracy | −20 / +40 seconds per day |
| Running time / battery life | Approximately 42 hours when fully wound |
| Jewels | 21 |
| Movement size | 11½ lignes; 26.00 mm diameter |
| Movement height | 5.67 mm |
| Battery | Not applicable |
What this means on your wrist
Automatic describes how the movement is wound. It does not mean the watch runs indefinitely when left unworn: once its stored energy is used, it stops and needs winding and setting.
The balance runs at 21,600 vibrations per hour. Mechanical accuracy is specified per day here; the Ronda quartz reference uses seconds per month. Compare the units as well as the numbers.
Ownership and compatibility
Miyota’s instructions say to avoid quick-setting the date between approximately 9 p.m. and 1 a.m., when the calendar mechanism is changing over. Follow the finished watch’s crown instructions as well.
For a commission, a shared nominal diameter does not make movements interchangeable. Case height, stem position, dial mounting, date opening, hands, and clearances all need checking.
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Manufacturer sources
Manufacturer specifications checked October 6, 2026. These are movement specifications, not a test report or a guarantee for an individual finished watch. Case size, water resistance, and materials are specified on each watch’s product page.