After 1765, kin-za and zin-za (see the article of gin-za [history]) also were in charge of the operation of casting coins and as a result gin-za which had been a contracting business by private merchants was under the regulation of kin-za.
明和2年（1765年）以降は金座および銀座(歴史)が鋳銭事業を兼任することになり、それまで主に民間の商人による請負事業であった銭座が金座の統制下に置かれる事となった。