It is Hyoki kahei, whose face value is written on the coins, while Chogin (collective term of silver) and mameitagin (a kind of Edo-period coins) are Hyoryo kahei (currency valued by weight), whose currency value is determined by weight.
丁銀や豆板銀が重量を以て貨幣価値の決まる秤量貨幣であったのに対し、額面が記載された表記貨幣である。