Part of the Miyota Cal. 8200 family, Cal. 8285 is a day-date central seconds automatic movement. Unlike the day-date Miyota 8205, Cal. 8285 features an outer day wheel, showing the day of the week in full at 12:00 instead of an abbreviation at 3:00. It is mono-lingual.
All members of the Miyota 8200 family have indirect seconds, which causes a noticeable wobble to the central seconds hand. When struck, the seconds hand can appear to pause for up to 2 seconds due to slack in the movement.
The movement can be manually wound with the crown in position 1. Rotate the crown clockwise to wind the mainspring.
The day and date wheels are advanced with the crown in second position (one notch out). Turn the crown counter-clockwise to advance the date wheel by one day. Turn the crown clockwise to advance the day wheel.
The date should not be set between 21:00 and 1:00 and the day should not be set between 1:00 and 4:30. Doing so risks damaging the movement.
The time is set with the crown in third position (pulled all the way out). Rotate the crown clockwise to advance the minute and hour hands and counter-clockwise to turn them backward.
| No Date | Date Only | Day-Date | |
| Hand Winding | 8270 8N33 SK | 8260 | |
| Automatic Central Seconds | 8228A OH 82S0 PS OH 8N24 SK 8N26 SK HH | 8210 8215 SR 821A | 8200 8203 8205 SR 820A 8285 SR OD |
| Automatic 24 Hour Hand | 8247 82D7 OH | 8217 | |
| Automatic Small Seconds | 8245 82S5 PS OH 8N40 PS | 8218 | |
| Automatic 24 Hour Hand Small Seconds | 82S7 PS OH | 8219 |
- OH = Open Heart at 7:00
- SK = Skeleton
- PS = Partial Skeleton
- HH = High Hands
- OD = Outer Date
- SR = Solid Rotor