Miyota Caliber 8315

Miyota caliber 8315

Miyota Caliber 8315 Wide

Manufacturer Miyota (Citizen)
Caliber Number 8315
Movement Type Automatic, self-winding mechanical
Diameter 26mm
Height 5.67mm
Jewels 21
Beat Rate
21,600 bph, 3 Hz
Lift Angle
49 degrees
See below…
Power Reserve
60 hours
Rotor Winding Direction Counterclockwise
Hand Windable?
Stem 065-212 (tap 10)
Dial Screws 929-610
Case Clamps
Case Clamp Screws
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?
Quickset Date?
“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:


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:

  1. 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.
  2. 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.
  3. 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.


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:

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2 years ago

The Miyota 8315 replaces the 821A. It is a hacking and decorated version or the Miyota 8215, that has now been upgraded with a new mainspring. The power reserve is now a minimum of 60 hours, and the movement is offered in silver and gilt versions.

Diameter: 11.5 Ligne/25.6mm
Height: 5.67mm
Jewels: 21
Complications: Date
Power Reserve: 60+ hours
Lift Angle: 51
Antishock: Parashock
Hand Sizes: 100/152/17
Dial Feet: 25/50

John le Carré
John le Carré
1 year ago
Reply to  HoustonReal

Very good and accurate text, @HoustonReal, lift angle is 51° – 53° though. Just helping here.

William Shatner
William Shatner
1 year ago
Reply to  John le Carré

@CC, I’ve measured my 8315’s lift-angle too. My Witschi-apparatus ensures me of the correct lift-angle of 52° (degrees).

John le Carré is thus fairly right though. Witschi is the correct Swiss measuring device, since a very long time, since I can remember anyways. No hard feelings, @CC.

Zdeněk Bartoš
Zdeněk Bartoš
6 months ago

It is 49, not 51, not 52, not 53. This site says 49. Miyota says 49. You are saying wrong lift angle and I first got the bad reading because setting was wrong. Now I get the good reading because I use the right setting at 49.

Don B
Don B
1 year ago
Reply to  HoustonReal

It appears to be a descent movement. I just installed one in my Bulova Devel Diver 666, replacing to 8215 that they use from the factory. I really prefer the hacking function and the stock movement was just not doing it for me. The 8315 is a direct drop in movement and no mods were required. My unit is currently at +2 seconds with no beat error. I will run it for a couple weeks and then recheck. The hacking is instant and easy to accomplish. Setting appears to be the same slightly loose feel that you get with the… Read more »

5 months ago
Reply to  Don B

Where were you able to find an 8315?

William Shatner
William Shatner
1 year ago
Reply to  HoustonReal

HoustonReal, you’re spot-on ( what’s a 1° deviation in your and my measurements (?) – it’s close enough, ey ?! 😉 )

I too find it a feisty little 8315-caliber. Another big win for Citizen ánd Miyota alike.

6 months ago

Hi! I have a Laco “BIELEFELD 42” configured with this movement (they call it Caliber 31). It has 69 hours of power reserve (until it stops), measured a few times in the last 2 months. During normal daily wear, it runs about +2s a day. It has the “hacking” feature when setting the time. Another great movement by Miyota.

26 days ago

Is the seconds hand on the 8315 direct drive?

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