Miyota Caliber JR10 Watch Movement

Manufacturer	Miyota
Caliber Number	JR10
Movement Type	Quartz, battery-powered
Lignes	12.5”’
Diameter	28.2mm
Height	4.18mm
Jewel Count	No jewels (0)
Frequency	32,768 Hz
Battery Cell #	SR621SW / 364
Battery Life	3 years
Stem Part #	065-505 (tap 10)
Hand Count	6
Hand Sizes	1.2mm (hrs) / .70mm (mins) / .17mm (secs) / 3 x .26mm (subdials)
Functions	Central hours; central minutes; central seconds; date subdial at 12:00; retrograde day of the week at 6:00; 24 hour subdial at 9:00
Hacking Seconds?	Yes
Country of Manufacture	Made in Japan
Known Models	(Add your watches to the comments below…)

The Miyota caliber JR10 is a multi-functional quartz movement with a day-date calendar complication. Based on official documentation, this movement has been available since at least February 2008.

As of this caliber listing, the JR10 has been discontinued.

Some of the topics covered in this caliber listing:

Notable Features:

The JR10 has a pointer date subdial at 12:00, along with a fanning retrograde day of the week centered at 6:00. Additionally, the 9:00 subdial displays a 24 hour hand, useful for military time or as a day/night indicator.

Similar Calibers:

The JR family of multi-function movements also includes JR00 and JR20. The differences are the layout of the subdials and retrograde DOTW:

JR00 – Date at 12:00; retrograde day at 4:30; 24 hour indicator at 9:00
JR10 – Date at 12:00; retrograde day at 6:00; 24 hour indicator at 9:00
JR20 – Date at 3:00; retrograde day at 6:00; 24 hour indicator at 9:00

Notes about setting the calendar:

Do not attempt to set the date while the hands are between the hours of 9:00 PM and 1:00 AM.

Do not attempt to set the day while the hands are between 11:00 PM and 3:00 AM.

Do not stop advancing the day of the week hand when the hand is pointing to the middle of the markers – always complete the advancement so that the hand is pointing to the marker. If by chance the hand lands between the markers, simply slowly turn the crown clockwise until it is pointing toward the correct marker.

Replacement Prices:

Despite the calibre JR10 being discontinued, at the time of this post it is readily available from various watch parts suppliers. Replacement prices were found in the range of $11.00 USD to $26.95 USD.

Additional Resources: