20 Sen

These small-denomination notes entered circulation as a direct consequence of wartime metal shortages — Japan's participation in World War One created enough demand on silver and copper that subsidiary coinage became impractical to maintain at volume. Paper filled the gap. The Printing Bureau produced the series domestically, which was still notable at the time; earlier Japanese paper currency had frequently relied on foreign printers, particularly in the Meiji period.

The series was short-lived by design, retired once metal supplies stabilized postwar. Surviving examples in any condition above heavy use are genuinely uncommon — these were working notes in a period of active commerce.