Citizen Caliber 8310

Brand	Citizen Watch
Caliber Number	8310 (8310A?)
Manufacturer	Miyota (Citizen)
Movement Type	Automatic, self-winding mechanical
Lignes	11.5”’
Diameter	26mm
Height	5.67mm
Jewels	21
Beat Rate	21,600 bph
Lift Angle	49 degrees
Power Reserve	60 hours (at least)
Winding Direction	Uni-directional (left)
Anti-Shock System	Parashock
Functions	Central hours; central minutes; central sweeping seconds; date at 3:00
Hacking Seconds?	Yes
Country of Manufacture	Japan
Known Models	Citizen Tsuyosa Collection (Refs: ), Citizen JDM “NK” Collection (Refs: NK0000-95E, etc) (Add your watch in the comments below…)

The Citizen caliber 8310 is a self-winding automatic movement with 21 jewels. Several time+date 3-hand dress watches with this movement were introduced in September 2019. This caliber is made in Japan.

Citizen 8310 VS Miyota 8310:

Although this caliber is exclusive to Citizen, it is made by Miyota, which is part of Citizen Watch. With there also being a similar Miyota caliber 8315, there is often caliber confusion with some members of the community looking for information regarding “Miyota 8310”. Please note: technically this is the Citizen caliber 8310 and not Miyota 8310 (even if it produced by Miyota).

Citizen 8310 VS 8210:

There is a similar Citizen caliber 8210, and auto with 3 hands and a date at 3:00. The 8310 appears to be an evolution of that movement, with the main difference being that the 8210 offers a power reserve of at least 40 hours and the 8310 has a runtime of 60+ hours. At the time of this caliber listing, Citizen’s official site (at least the site shown to North American and English speaking customers) does not return any search results for “8310”. In fact, searching for 8310 simply displays 5 “Tsuyosa” Collection timepieces, all powered by the 8210 (see below).

Accuracy Rating:

The accuracy of the Miyota version of the 8310 (Miyota 8315 as mentioned above) is -20~+40 seconds per day. The Citizen 8310 can be expected be within that range or better.

Additional Resources:

• List of Miyota movements
• More Citizen calibers