Wuyi or 51 (referencing May 1st) was Tianjin Watch Factory's first general distribution, large production wristwatch, followed by the Dongfeng (East Wind) brand, then Sea-Gull.
62-a Movement shot:
I see that a reissue/homage is on sale right now at the Seagull website.
Very nice simple watch.
Curator: Alberta Museum of Chinese Horology in Peace River; Member: China Horologe Association; Chief Expert: China Watch Overseas Working Committee (CWOWC); Sino-Canadian Horological Cultural Affairs...