I just imaged 108 world coins I got in bulk, and I don't know what these 2 are, or where they're from. Coin 1 - Coin 2 -
Both Japanese. I think the first one is a one yen - Showa. 1957. https://en.numista.com/catalogue/pieces1590.html I think the second one is https://en.numista.com/catalogue/pieces5438.html. Check out those numista sites and the dating will become obvious. If you didn't know, each emperor chooses a name for his reign. Hirohito chose Showa for the name of his reign. See https://en.wikipedia.org/wiki/Shōwa_(1926–1989).
Japanese coins are relatively easy to identify as Japanese - look for that one character that looks like a box with a horizontal line through it (ri4).
Second one is indeed a 10 sen, Showa 15 = 1940 They kept making the wartime aluminum 10 sen thinner and lighter as the war went on.
Only 2 are the same year. They are: L: Showa 16 (1941) 1.5 g C: Showa 16 (1941) 1.2 g R: Showa 18 (1943) 1.0 g 1.5 g was made 1940-41, 1.2 g from 1941-43 and 1.0 g for 1943 only. After that they were tin-zinc in 1944, some ceramic ones were briefly issued in 1945, and they aluminum again postwar in 1945-46.
