Since the Ansei Treaty had been signed, foreign merchants were allowed to buy Japanese goods with foreign silver coins, and their exchange rate at that time was 311 ichibu-gin silver coins against 100 Spanish dollar.
安政条約によって外国商人が外国銀貨で日本の商品を購入することが許されたが、当時の質量に基づく相場はSpanishdollar100枚に対して一分銀が311枚であった。