As kin-za (an organization in charge of casting and appraising of gold during the Edo period) and gin-za concurrently took charge of mintage of coins after 1765, zeniza was established as a fixed guild and the bakufu strengthened the control of mintage and tried to homogenize coins.
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、定座としての銭座が確立し、鋳銭に対する幕府の支配が強化され、銭貨の均質化が図られた。