室町初期〜中期

After the reunification of the courts in 1392, Ashikaga Yoshimitsu brought the Muromachi shogunate to its zenith, nurturing the Kitayama and Higashiyama cultures. In this stable era, demand for ōdachi declined, and swords shifted from Nanbokuchō grandeur to more moderate proportions. Blade lengths settled around 70-73 cm with slightly narrower widths, and elegant forms with saki-zori (curvature toward the tip) became standard. In Bizen, Osafune Morimitsu and Yasumitsu developed the 'Ōei Bizen' style—refined, dignified works that earned high regard in later centuries. Mino's Seki smithing community grew in strength, with Kanetsune and Kanefusa producing many practical swords. The Nobukuni school continued in Kyoto, and the Yamato tradition's Kanenaga lineage remained active. During this period, massive quantities of Japanese swords were exported to Ming China as part of Japan-Ming trade, with Osafune Bizen as the primary production center. This era before the Ōnin War (1467) is characterized by relatively gentle workmanship within the late kotō period—a transitional time between Nanbokuchō boldness and sue-kotō practicality—valued by discerning collectors.