It is "Zhongshan Watch", not "Zhongshan Watch". This watch is produced by Nanjing Watch Factory.

The predecessor of Nanjing Watch Factory was Jiangnan Clock Factory. It was a public-private partnership in 1956. In 1957, the factory moved to Sifang City outside Zhongshan Gate, Nanjing. The first batch of watches developed were the Purple Mountain brand. In 1959, the watch business was split and the Nanjing Watch Factory was established. From 1959 to 1960, the five-diamond Zhongshan watch was developed and produced. Around 1974, the finalized nine-diamond Zhongshan watch was produced, and Zhongshan watch production entered a mature stage. From 1976 to 1984, Zhongshan watches were at their peak, with annual output reaching 2.2 million in 1984. Therefore, the production of Zhongshan watches in the 1970s was already very large. In addition, the workmanship was rough and the ornamental value was poor, so the collection value was not high. Now it’s generally around 300 yuan, and it’s not easy to get one.