10 Sen - Shōwa

By 1944, Japan's wartime aluminum allocation for coinage was itself under pressure — the same metal was critical for aircraft production, and the government had already cycled through tin, zinc alloys, and clay as emergency substitutes for other denominations. This issue survived the transition, but barely; production was erratic and mint records from the final war years are incomplete.

Surviving examples that saw actual circulation are considerably scarcer than mintage figures suggest. Much of the late-war issue was hoarded or simply never distributed before the August 1945 surrender disrupted normal monetary channels entirely.