Shanghai Watch Factory Caliber A581

Manufacturer	Shanghai Watch Factory (上海)
Caliber Number	A581, A-581, 581
Jewels	17
Beats per hour	18,000 vph
Power Reserve	40 hours
Anti-Shock System	None
Hand-Windable?	Yes
Hacking Seconds?	Yes
Functions	Hours, minutes, central seconds
Country of Manufacture	China
Known Models	(Add yours to the comments below…)

The Shanghai caliber A581 is a 17 jewels (17 zuan) manual wind mechanical movement. It is based off the A. Schild caliber AS 1194. This caliber was produced from circa March 1958 – 1967. This caliber does not have the following: no anti-shock protection system; no adjustment screws on the balance wheel; no fixing screw on the main bridge.

Similar movements in this family include the Shanghai caliber A611 with an anti-shock system, as well as the caliber A623 with a date complication.