As the kan was also used as the currency unit (1 kan equals 1,000 mon; in the Edo period, 1 kan equaled 960 mon under the Shohaku method [currency exchange rate in Edo period]; in the Meiji period, 1 kan equaled 10 sen), the kan for representing mass was called kanme, while that for representing the currency was called kanmon, to make clear the difference between them.
貫は通貨の単位（1000文。江戸時代には一般的に省陌法と称して960文。明治時代には10銭）としても用いられたので、区別のために質量の方は貫目、通貨の方は貫文と呼んだ。