| Manufacturer | Miyota (Citizen) |
| Caliber Number | 8315 |
| Movement Type | Automatic, self-winding mechanical |
| Lignes |
11.5”’ |
| Diameter | 26mm |
| Height | 5.67mm |
| Jewels | 21 |
| Beat Rate |
21,600 bph, 3 Hz |
| Lift Angle |
49 degrees |
| Accuracy |
See below… |
| Power Reserve |
60 hours |
| Rotor Winding Direction | Counterclockwise |
| Hand Windable? |
Yes |
| Stem | 065-212 (tap 10) |
| Dial Screws | 929-610 |
| Case Clamps |
082-060 |
| Case Clamp Screws |
924-460 |
| Anti-Shock System | Parashock |
| Hand Sizes |
1.50mm / 1.0mm / 0.17mm |
| Functions | Central hours; central minutes; central sweeping seconds; date calendar at 3:00 |
| Hacking Seconds? |
Yes |
| Quickset Date? |
Yes |
| Finishing |
“Fine finishing” decoration on the barrel bridge; blued screws on the oscillating weight, barrel bridge, and balance cock |
| Country of Manufacture | Japan |
| Known Models | (Add your watch in the comments below…) |
The Miyota caliber 8315 is a 21 jewels automatic movement, made in Japan. It is part of Miyota’s line of “Standard Automatic” watch movements, but what sets this calibre apart from the others is that is has a longer running time with more than 60 hours power reserve. Miyota states that this is their longest running mechanical movement.
Some of the topics covered in this caliber listing:
Accuracy:
Miyota claims that the cal. 8315 has an average accuracy rating of -20 / +40 seconds per day in normal operating conditions.
Time and Date Setting:
As a basic 3-hander with a date, setting the 8315 is straightforward. There are 3 crown positions:
- Crown against the case – Manual winding: full power serve is reached when the crown is turned at least 51 times. You cannot over-wind the movement.
- Crown pulled out one click – Date setting mode: turning the crown counterclockwise will advance the calendar datewheel. Do not make this adjustment when the hands are between the hours of 9:00pm and 1:00am.
- Crown pulled out two clicks – Time setting mode: rotate the crown to set the time of the hands. The seconds hand will be hacked in this mode (aka stopped for precise time-setting).
Replacement Prices:
At the time of this post, replacement pricing for the Miyota 8315 was found online in the range of $85 to $89.95 USD. When ordering bulk from Miyota, the minimum order quantity is 100 pieces.
Compatibility:
The 8315 is based on the 8200 series framework. Therefore, it is compatible with most caliber 82XX dials, hands, and cases (such as the popular Miyota 8215).
Additional Resources:
network of watch sites
