15 Yen - Government bond

Japan's wartime bond-note hybrids occupy a strange corner of the catalog. The Nippon Kangyo Bank — a semi-governmental agricultural and industrial credit institution founded in 1897 — served here as the nominal issuing vehicle for what was effectively a state war-finance instrument. By 1942, Japan's military expenditures had stretched ordinary budget mechanisms past their limits, and these government bond notes represented one mechanism for mobilizing domestic capital without triggering the full inflationary optics of direct currency printing.

The 15-yen denomination is itself a tell: round-number bonds serve retail savings markets; odd denominations like this typically reflect a specific interest-plus-principal redemption structure baked into the face value at issue.