1 Sentimo

The BSP's aluminium sentimo issues of this period were produced under Ferdinand Marcos's "Bagong Lipunan" (New Society) coinage reform, which restructured Philippine currency following the 1972 declaration of martial law. The reform was partly practical — chronic shortages of small-denomination coins had plagued daily commerce for years — and partly political, with the new series serving Marcos's broader effort to brand his authoritarian government as a modernizing force.

Aluminium at this denomination was a deliberate cost-reduction choice; the metal's low density meant striking costs were negligible against face value.