Gong, manufactured by Ludong Factory, China, with test mark

This is a gong purchased 39 years ago at the Friendship Store in Shanghai, China. I don't remember the exact price, but I think it was around 100 yuan. At the exchange rate of the time, that was about 3,900 yen, which was roughly the monthly salary of an urban worker back then. It is said to be equivalent to 100,000 to 200,000 yen in today's Japanese currency. This brass gong produces a beautiful resonant sound. If you are interested, please consider it.
The size is 33cm in diameter, and the mallet is 23cm long. The body is about 2mm thick and weighs 1.35kg, making it quite heavy. There is a stamp on the back, Lu Dong Bing Qi Chang (魯東兵器廠), which is a mark of inspection (≒ certification). Lu Dong Bing Qi Chang is a general term for military production bases in eastern Shandong province during the Anti-Japanese War and the Civil War period, and it is a manufacturer with a distinguished history (?).