Miyota Caliber 6S50

Manufacturer	Miyota (Citizen)
Caliber Number	6S50 (sometimes typed as 6S5O)
Type	Quartz
Replaces Caliber	Unknown, please add in the comments below
Diameter	15”’ (34.60mm)
Height	5.95mm
Total Height	8.5mm
Battery Cell Number	SR927W (395)
Battery Life	Approximately 4 years
Frequency	32,768Hz
Quartz Type	Tuning fork type quartz crystal
Stem	065-A13 (tap 10)
Hand Sizes	120mm/70mm/17 (small hands also 26mm)
Jewels	0
Functions	Hours, minutes, central chronograph seconds, 1/20 seconds subdial at 3:00, small seconds at 6:00, 60 minutes totalizer at 9:00, big double digit date at 12:00
Country of Manufacture	Japan
Known Models	AVI-8 Hawker Harrier II Matador (add yours to the comments below…)

The Miyota caliber 6S50 is a quartz chronograph watch movement. It is made in Japan and has 0 jewels.

Accuracy

Miyota claims the accuracy of this movement to be +/-20 seconds/month.

Battery Life

According to Miyota, the correct SR927W battery cell should last about 4 years. It’s important to note that running the chronograph means the watch is working harder and this reduces the battery life. It’s advised to only use the chronograph when you need it. If you are not going to wear your watch for a while and want to save the battery, pulling out the stem (aka hacking the movement) will reduce the battery consumption.

Resetting the chronograph to zero

If your chronograph hand is not resetting to 12:00 or “zero” position, then you can try the following steps:

1. Pull the crown to position 2 (time setting position).
2. Press button A to advance the chronograph hand forward until it is lined up with 12:00. If you long-press A, the hand will move forward faster.
3. Press button B to advance the 1/20 second subdial.
4. Push the crown back to position 0

Note: if you push the crown back in to position 0 while the chronograph hand is still advancing forward, then it will stop the chronograph hand and recognize it as zero position. In this case, you will have to start over again.

Replacement prices

The average replacement price at the time of this post was from $25 – $29.95.  Buy it here.

Assembly Warning: Blowing the Big Date

The Miyota tech sheets have been updated to include a huge warning about not using a blower to clean dust unless the big double digit date is set to either 09, 19, or 29.

Interesting side note: it’s also interesting that this warning was written in English and Chinese, not Japanese even though the movement is made in Japan. Presumably this is because the official documentation exists in Japanese, but most likely it’s because the two main markets using this movement are the Chinesse factories that build most of the microbrands and the American brands that sell them.

Examples of watches with Miyota caliber 6S50

The Miyota 6S50 found in an AVI-8 Hawker Harrier II watch

Additional Resources:

• Official movement sheet
• Official tech sheet
• Order a replacement 6S50