2 Mun Kum, Extend

The "Extend" (통보 상평통보 계열) series of cash coins was struck at multiple government arsenals and military offices simultaneously — the issuing bureau is encoded in the reverse inscription rather than tracked by mint mark in the Western sense. By 1753, the Joseon court had been managing chronic copper shortages for decades, periodically suspending and resuming cash coinage as bullion supplies fluctuated. The 2 Mun denomination was a deliberate policy instrument, introduced to reduce the quantity of metal per transaction value rather than simply strike more 1 Mun pieces.

Identifying the specific casting bureau from KM#379 examples requires close reading of the reverse characters — variations exist across at least a dozen offices.