1 Sen - Shōwa Pattern

This 1945 brass pattern was produced as Japan scrambled to adapt its coinage to wartime material shortages — by this point the military had consumed most available base metals, and the government was experimenting with whatever substitutes could be sourced domestically. Pattern pieces from this period rarely made it to full production approval before defeat in August rendered the entire exercise moot.

KM#Pn73 is one of several competing alloy trials from the final months of the war, most of which survived only in proof or trial quantities held by the mint.