According to Tsurugi no maki (chapter titled "Tsurugi" or sword) of Heike Monogatari (The tale of the Heike), the sword craftsman was "a craftsman of iron facon from Tang who lived in Deyama, Mikasa no Kori, Chikuzen Province," however, the details are unknown.
平家物語・劒の巻では、刀工は「筑前国三笠郡の出山というところに住む唐国の鉄細工」とされているが詳しいことは不明。