As Emperor Suiko composed, 'A colt from Hyuga Province is the best horse, and Masabi from Wu is the best Tachi,' swords from Wu (collective name of southeast area of China) was supposed to be the best during this period.
推古天皇が「馬ならば日向国の駒、太刀ならば呉のまさび」と詠んでいるように、この時代、呉（中国南東部の総称）の刀が最良とされていた。