10 Sen Netherlands East Indies

Japan began issuing coinage for the occupied Netherlands East Indies in 1942 following the rapid collapse of Dutch colonial defenses, replacing the existing Dutch colonial currency as part of a broader effort to reorient the archipelago's economy toward Japanese war aims. Tin-zinc was chosen out of necessity — by 1943, copper, nickel, and aluminum were all being consumed by the Japanese military machine at a rate that made them unavailable for subsidiary coinage.

The tin-zinc alloy proved notoriously unstable, and surviving examples that have not corroded, cracked, or suffered surface breakdown are genuinely scarce.