It is said that the entire ship was covered with fireproof iron plates to prepare against attacks by horoku-hiya (one type of fire arrows) at which the Murakami navy was good.
村上水軍が得意とする焙烙火矢による攻撃に対抗するため、船全体を防火用の鉄板で覆ったものであったと伝えられる。