noun
Kan'ei Tsūhō; copper coin of the Edo period
A round copper coin with a square hole, minted from 1626 (Kan'ei era) and widely used throughout the Edo period. The name is often used as a generic term for Edo-period copper coins.
寛永通宝は江戸時代を通じて広く流通した銅貨です。
The Kan'ei Tsūhō was a copper coin widely circulated throughout the Edo period.
The name combines the era name 寛永 (Kan'ei) with 通宝 (tsūhō, 'circulating treasure'), a common naming pattern for East Asian coins. The exact derivation is straightforward from the era and coin terminology.