The Miyota caliber 8247 is an automatic watch movement with a small seconds and calendar complications. This movement is from the affordable 8 Series family of what Miyota refers to as “Standard Automatics”, further categorized as “Small Hands”. As of 8/2022, this caliber is no longer present in Miyota’s current catalog.
Some of the topics covered in the caliber listing:
Cal. 8247 is based off of 8215/821A framework but with a small seconds subdial in the 4:30 region rather than a central sweeping seconds hand. This small seconds hand option may be a good solution to the Miyota jumping seconds that so many watch collectors experience with other 82XX calibers. Since the seconds hand is smaller and not centralized, any stuttering or jumping may not be as noticeable. Please comment below if you have this caliber and have experiences it.
Miyota 8247 VS 8245:
There is a similar caliber 8245 with the main difference being that the 8247 has an additional 24 hour hand complication located at 9:00. Other than that, these two calibres are the same.
8245 VS 8218:
The caliber 8218 is the same as the 8245 but without a calendar complication. The caliber 8218 has a date at 3:00.
Accuracy & Power Reserve:
Miyota claims that the caliber 8247 offers accuracy of -20 ~ +40 seconds per day under normal operating temperatures, and when measured with a full power reserve.
“Accuracy of the mechanical watch is different from the daily rate of the quartz watch and the accuracy will change maximum of several ten seconds during rewinding the spring, then the accuracy of the half winding condition will be different from that of full winding condition.” -Miyota official tech sheets
When fully wound, the power reserve is about 40 hours of running time. To reach full power reserve via manual winding, turn the crown 40 times.
At the time of this post, replacement prices for the caliber 8247 were found online in the range of $49.95 – $56.58 USD. Supply seems to be limited since this exact caliber number appears to be discontinued and no longer offered by Miyota.