The specified composition of coins minted at this time was changed to 75% of copper, 15% of zinc, and 10% of lead and so on, and the coin was called Aka-sen (literally, "red coin") because of reddish coin.
このときのものは規定品位が銅75%、亜鉛15%、鉛など10%へ変更となり、赤みを帯びることから赤銭（あかせん）と呼ばれる。