Miyota Caliber 0S20 Watch Movement

Miyota caliber OS2O 0s20 — Example of a Miyota 0S20 in a Philip Stein Extreme Chronograph Watch

Manufacturer	Miyota (Citizen)
Caliber Number	0S20 (sometimes typed as OS20)
Type	Quartz
Replaces Caliber	Unknown, please add in the comments below
Diameter	13.50”’ (30.80mm)
Height	5.1mm
Battery Cell Number	SR927W (395/399)
Battery Life	Approximately 5 years
Frequency	32,768Hz
Quartz Type	Tuning fork type quartz crystal
Stem	065-441 (tap 10)
Hand Sizes	1.20/.70/.17 (small hands also .26)
Jewels	0
Functions	Hours, minutes, central chronograph seconds, 60 minute counter, 24 hour hand, date
Country of Manufacture	Japan
Known Models	Bulova chronograph, Philip Stein Extreme Chronograph, TW Steel A1GP Chrono, Invicta Speedway Chronograph Original Version (Too many to list, add yours to the comments below…)

The Miyota caliber 0S20 is a quartz chronograph watch movement. You might also see other listings incorrectly refer to this movement at OS2O, but is should be zero-S-2-zero not O.

Some of the topics covered in this caliber listing:

Accuracy:

Miyota claims the accuracy of this movement to be +/-20 seconds/month.

Recalibrating the chronograph hand to zero:

It is common for a quartz chronograph hand to be misaligned after a battery change. If your central chronograph second hand (or chronograph minute hand) is not resetting to 12:00 or “zero” position, you can try the following steps:

Pull the crown to position 2
Press button A (top button) to advance the chronograph hand forward until it is lined up with 12:00. If you long-press A, the hand will move forward faster.
Push button B (bottom button) to reset the 60 minute chronograph hand (subdial located at 9:00).
Push the crown back to position 0

Note: if you push the crown back in to position 0 while the chronograph hand is still advancing forward, then it will stop the chronograph hand and recognize it as zero position. In this case, you will have to start over again.