20 Yen US Military Currency - B-Note

The B-yen series was issued by Allied occupation authorities following Japan's surrender in August 1945, specifically to prevent the existing Japanese military from drawing on domestic currency stocks to fund any continued resistance or postwar destabilization. The "B" designation distinguished these notes from regular Bank of Japan issues, and Japanese banks were instructed to accept them at par — a directive that generated significant friction with the Bank of Japan from the outset.

Inflation eroded the series badly. By 1948, B-yen purchasing power had collapsed alongside the broader occupation-era monetary disorder, and the notes were eventually superseded when SCAP imposed a single fixed exchange rate of 360 yen to the dollar in April 1949.