By 1943, Japan's wartime aluminum allocation had become so constrained that the government was simultaneously reducing coin weights and requisitioning existing metalware from civilian households. This 1-sen piece was struck at just 0.55g — roughly half the weight of its prewar aluminum predecessors — as the military supply chain consumed priority stocks. Production was discontinued entirely the following year, making the 1943 issue the final year of the denomination in circulation.
By 1943, Japan's wartime aluminum allocation had become so constrained that the government was simultaneously reducing coin weights and requisitioning existing metalware from civilian households. This 1-sen piece was struck at just 0.55g — roughly half the weight of its prewar aluminum predecessors — as the military supply chain consumed priority stocks. Production was discontinued entirely the following year, making the 1943 issue the final year of the denomination in circulation.