1 Peso

Apayao was one of the most isolated sub-provinces in the Mountain Province of northern Luzon, and its emergency currency was issued under the Philippine Commonwealth's guerrilla administration following the Japanese invasion of late 1941. Local governments across the Philippine archipelago were authorized — or simply compelled by necessity — to print their own emergency notes when central supply lines collapsed entirely.

The S109 designation places this among the Philippine guerrilla issues catalogued in Pick's specialized listings, a category notorious for wide variation in paper quality and hand-stamped authorizations. Apayao's extreme geographic isolation meant these notes circulated within a very limited area, and surviving examples are genuinely scarce relative to better-documented lowland issues.