Especially because at the time, the currency system centered around Europe and America was mainly the gold standard system, along with the fact that the shape of the koban (former Japanese oval gold coin) of this period was inconvenient for external transport and circulation, instead, the coining of counterfeit nibukin, which was the most used in the field of external settlement, was done frequently, and even gilded silver coins which were not so different from the forfeit coins appeared.
特に当時の欧米を中心とした通貨制度の主流が金本位制であったこと、当時の小判の形状が対外的な運搬・流通などに不便であったことから、代わりに対外決済の分野で最もよく使われていた二分金の贋貨鋳造が盛んに行われ、中には銀貨に金鍍金を施した贋貨とほとんど変わりのないものまで出現した。