10 Yen - Shōwa Smooth edge

The smooth-edge 10 yen replaced the reeded-edge Y#73 in 1959 — a quiet production change with no official public announcement. Japan's postwar economic recovery was accelerating sharply by then, and the 10 yen coin was one of the most actively circulated denominations, which makes genuinely uncirculated examples from the early Shōwa smooth-edge years harder to locate than mintage figures alone would suggest. Issues from the mid-1980s onward survive in higher average grades as vending machine infrastructure reduced coin-to-coin contact wear.