Shanghai Watch SM1A

The SM1A is an automatic movement manufactured by Shanghai Watch, notable as an exception to the Tongji standardization framework that guided much of the company's production. As an in-house caliber, it represents Shanghai Watch's independent development capabilities during a period when many Chinese manufacturers relied on standardized movements. The movement was discontinued at some point, and specific technical specifications such as diameter, frequency, power reserve, and jewel count are not publicly documented. It stands as a historical example of Shanghai Watch's efforts to produce proprietary automatic movements outside the Tongji system.