In Tsurugi no maki (chapter named "Tsurugi" (sword)) of Heike Monogatari (The Tales of the Taira family), it says that the swordsmith was 'a craftsman of iron from Tang (China) living in a place called Deyama in Mikasa Gori, Chikuzen Province,' but the full details are unknown.
平家物語・剣巻では、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。