S. Epson Caliber VX36 Watch Movement

Manufacturer	S. Epson Corp. (Seiko)
Caliber Number	VX36, VX36A, VX36B, VX36E, etc.
Movement Type	Quartz, battery-powered
Lignes	10.5”’
Diameter	24mm x 21.5mm
Casing Diameter	23.3mm
Height	3.05mm
Jewel Count	0 (no jewels)
Frequency	32,768 Hz
Accuracy Rating	+/- 20 second per month
Battery Cell	SR920SW (371/370)
Battery Life	3 years
Regulator	None
Stem	0351177 (tap 10, 0.9mm) or 0351578
Hand Count	5
Hand Sizes	1.10mm / .65mm / .20mm + 2x .21mm for the day/date
Functions	Central hours; central minutes; central seconds; pointer style day of the week subdial at 9:00; pointer style date subdial at 3:00
Hacking Seconds?	Yes
Country of Manufacture	Made in Japan
Known Models	Android by Aragon Armor-15 (Add your watch to the comments below…)

The S. Epson caliber VX36 is a quartz movement with bi-compax style day/date indicators. This movement is sometimes also labeled as Hattori VX36.

You may see watches with this movement be incorrectly described as being “chronograph” watches, but that it because of day/date subdials which look like chronograph subdials from a distance.

Some of the topics covered in this caliber listing:

Setting the Time/Date:

To set the time, pull the crown out two clicks to time-setting mode.
To set the quickset style date, pull the crown out one click.
There is no quickset day of the week. In order to set the day of the week, you must pull the crown out two clicks to time-setting mode and advance the hands until the correct day is reached.

VX36A, B, C, D, E Variations:

The trailing letter on the end of the caliber number indicates an evolution in the movement. At the time of this post (1/24) the VX36 is up to VX36E. The differences between these variations is still unconfirmed. If you have any information regarding this, please comment below…

Technical documentation was found dated as far back as 8/2014, with updates as recent as 1/2019 and 9/2020. Although it is unknown how these updates affected the letter variation, it appears that the recent 9/2020 update was related to hand height and new part numbers for hand height options (usually to accommodate thicker dials).

S. Epson VX36 VS Pulsar V336:

While the VX36 is considered a modern replacement for the vintage Pulsar V336, there are some differences – none of which affect the usability or features of the movements, but technical differences that may impact individual parts interchangeability. Battery life and accuracy are the same. Some of the differences include: