Skip to content
WatchtheDetails

Movement · Miyota (Citizen) · automatic

Miyota 821A movement

Miyota 821A is an automatic movement by Miyota (Citizen): 5.67 mm1 high, 211 jewels, beating at 21,600 bph1, 42 h1 of power reserve.

Sources checked · How we source numbers
Miyota 821A: movement drawingMiyota 821A, dial side, to scale: movement diameter — (unknown); height 5.67 mm; hour, minute, second hand hole Ø — (unknown).movement Ø —5.67SIDE · SECTION · height 5.67Ahour, minute, second hand hole Ø —DETAIL A · 10:1
Miyota 821A, dial sideDrawing from data, not a photo · mm

Miyota 821A at a glance

Height
5.67 mm1
Jewels
211
Beat rate
21,600 bph1
Power reserve
42 h1
Accuracy
−20 to +40 s/day1
Lift angle
49°1
Do not set the date
21:00–01:001

New to the terms? Read quartz vs automatic or watch movement types.

Setting and servicing the Miyota 821A

The figures a watchmaker or a timegrapher needs for the Miyota 821A, as Miyota prints them.

Lift angle
49°1
Accuracy (maker)
−20 to +40 s/day1
Positional difference
50 s/day1
Power reserve
42 h1
Do not set the date
21:00–01:001
Hand winding
Yes1
Crown turns to full wind
401

What fits the Miyota 821A

The figures a dial, hands or case must match for the Miyota 821A, as Miyota prints them.

Stem part number
065-2121

Same family at Miyota

How each differs from the Miyota 821A, worked out from the figures on its own page.

What can replace the Miyota 821A

6 calibres of the Miyota 82xx group checked against the Miyota 821A: diameter, height, hand holes, date window, crown and dial feet. A verdict marked “not confirmed” lacks one of those figures for the Miyota 821A or the other calibre.

Not published, so not checked in several comparisons:

  • diameter for Miyota 821A
  • hand holes for Miyota 821A, Miyota 8215, Miyota 8315, Miyota 82S0, Miyota 82S5, Miyota 82S7 and Miyota 8N24
  • date position for Miyota 821A and Miyota 8315
  • crown position for Miyota 821A, Miyota 8315, Miyota 82S0, Miyota 82S5, Miyota 82S7 and Miyota 8N24
  • dial feet for Miyota 821A, Miyota 8315, Miyota 82S0, Miyota 82S5, Miyota 82S7 and Miyota 8N24

  1. Miyota 821A → Miyota 8215

    Fits with changes· not confirmed
    • ?diameterDiameter not published for both: the case seat cannot be checked.
    • =heightSame height: 5.67 mm.
    • ≠dateMiyota 8215 has no day wheel: a day-date dial would show an empty day window.

  2. Miyota 821A → Miyota 8315

    Fits with changes· not confirmed
    • ?diameterDiameter not published for both: the case seat cannot be checked.
    • =heightSame height: 5.67 mm.
    • ≠dateMiyota 8315 has no day wheel: a day-date dial would show an empty day window.

  3. Miyota 821A → Miyota 82S0

    Fits with changes· not confirmed
    • ?diameterDiameter not published for both: the case seat cannot be checked.
    • =heightSame height: 5.67 mm.
    • ≠dateMiyota 82S0 has no day wheel: a day-date dial would show an empty day window.
    • ≠dateMiyota 82S0 has no date: a dial with a date window would show nothing in it.

  4. Miyota 821A → Miyota 82S5

    Fits with changes· not confirmed
    • ?diameterDiameter not published for both: the case seat cannot be checked.
    • =heightSame height: 5.67 mm.
    • ≠functionsMiyota 82S5 adds a small seconds: it needs a dial and hand set made for it.
    • ≠dateMiyota 82S5 has no day wheel: a day-date dial would show an empty day window.
    • ≠dateMiyota 82S5 has no date: a dial with a date window would show nothing in it.

  5. Miyota 821A → Miyota 82S7

    Fits with changes· not confirmed
    • ?diameterDiameter not published for both: the case seat cannot be checked.
    • =heightSame height: 5.67 mm.
    • ≠functionsMiyota 82S7 adds a small seconds: it needs a dial and hand set made for it.
    • ≠dateMiyota 82S7 has no day wheel: a day-date dial would show an empty day window.
    • ≠dateMiyota 82S7 has no date: a dial with a date window would show nothing in it.

  6. Miyota 821A → Miyota 8N24

    Fits with changes· not confirmed
    • ?diameterDiameter not published for both: the case seat cannot be checked.
    • ≠heightMiyota 8N24 is 0.12 mm thinner (5.55 mm vs 5.67 mm): the dial and hands sit lower, so a spacer or a different stem height may be needed.
    • ≠dateMiyota 8N24 has no day wheel: a day-date dial would show an empty day window.
    • ≠dateMiyota 8N24 has no date: a dial with a date window would show nothing in it.

All Miyota 821A figures

Every figure we hold for the Miyota 821A, with its source. Where sources disagree, each value is shown.

Size

Height
5.67 mm1

Running

Jewels
211
Beat rate
21,600 bph1
Power reserve
42 h1
Hands and functions
date, day1
Hand winding
Yes1
Crown turns to full wind
401

Accuracy and care

Accuracy (maker)
−20 to +40 s/day1
Positional difference
50 s/day1
Lift angle
49°1
Do not set the date
21:00–01:001

Fitting: dial, hands, stem

Stem part number
065-2121
Movement holder part
500-7101
Dial screw part
929-6101

Not published yet

  • Diameter: not published by Miyota
  • Hand holes: only in Miyota’s drawing; not read yet
  • Dial feet: not in the documents we read

Miyota 821A questions

What is the lift angle of the Miyota 821A?

49°, as Miyota prints it. Enter 49° on a timegrapher to read amplitude correctly for the Miyota 821A.

Source [1]

How accurate is the Miyota 821A?

Miyota rates the Miyota 821A at −20 to +40 s/day, measured under Miyota’s own test conditions; a worn Miyota 821A can run outside the −20 to +40 s/day range.

Source [1]

How long does the Miyota 821A run when fully wound?

About 42 h from a full wind, per Miyota; a full hand wind takes about 40 crown turns.

Source [1]

When should you not change the date on the Miyota 821A?

Not between 21:00 and 01:00, per Miyota: the Miyota 821A’s date change is engaged then, so move its hands past 01:00 before using the quick-set.

Source [1][2]

Does the Miyota 821A hack and hand-wind?

Hacking is not stated. It can be wound by the crown.

Source [1]

What can replace the Miyota 821A?

From the published figures, the closest is the Miyota 8215: fits with changes, not confirmed for every part, with 5 more in the same group. Diameter not published for both: the case seat cannot be checked.

More on movements

Sources

Documents checked · Report a wrong number

  1. 1Citizen Watch Co., Ltd. (MIYOTA) — Spec. sheet (821A) · pdf · read
  2. 2Citizen Watch Co., Ltd. (MIYOTA) — Instruction manual (821A) · pdf · read