zhimakaimen, This was a great post. Thank you.
The stamp on the receiver is definitely Japanese and is literally 38 style. The translation of trainer could very well be in Chinese. The Japanese operated all over China and had annexed Manchuria and Korea so the marking could be for conscripted soldiers or as an identification as a captured item by the Chinese. The reason I say this is because the Japanese shouldn't need a plate on the stock to identify it as a trainer due to the other markings on the receiver.
Many people ask me if I intend to learn Japanese so I can translate the stuff I have collected. I point out that I gave up on that when I met a Japanese man with a degree in Japanese literature who was completely stumped by some of the things I brought him for translation. Between the multiple forms of charachters and the simplification of the written language after 1945 I find it pointless for me to try to learn more than the numbers and a few basic charachters. Never mind the items that may be Chinese or Korean marked and forget about the stuff copied by Marines for sale to the Navy...LOL
I own firearms not to fight against my government, but to ensure I will not have to.