'Tenpō Mameitagin' Large 寳

Produced in response to a severe silver shortage during the Tenpō era, the mameitagin was an emergency measure — the Shogunate had already debased the standard ichibugin so aggressively that merchant confidence in official silver was near collapse. The irregular bean-shaped blanks were deliberately retained from older minting traditions to signal continuity with Edo-period precedent, even as the actual silver content bore almost no resemblance to earlier issues.

The "Large 寳" variety is distinguished by the size of the treasure character in the stamp, a die difference catalogued separately by Daizō Hartill precisely because multiple punch sets were in simultaneous use across the production run.