建武の新政と刀剣

Emperor Go-Daigo's Kenmu Restoration lasted barely three years (1333–1336), but its significance for sword history is disproportionate to its brevity. Having overthrown the Kamakura shogunate with the military assistance of warriors like Ashikaga Takauji and Nitta Yoshisada, Go-Daigo attempted to resurrect direct imperial rule modeled on ancient ritsuryō precedent. The regime systematically employed the imperial bestowal of famous swords—swords personally worn by the emperor—as a mechanism of political bonding with key warriors, reinvesting the ancient practice of御剣拝領 (sword-receiving) with intense political urgency. This use of the sword as the supreme token of imperial grace reinforced the sword's status as the preeminent symbol of political authority in Japanese culture. Swordmaking during these years was in dramatic transition: Bizen smiths Nagayoshi and Kanemitsu were producing the massive tachi and naginata that herald the great Nanbokuchō blade-enlargement era, while Sōshū school disciples of Masamune such as Hasebe Kunishige were pioneering the enlarged uchigatana form. When the restoration collapsed and Go-Daigo fled to Yoshino with the Three Sacred Regalia to found the Southern Court, the renowned swords of the Kenmu era became legendary objects caught in the whirlwind of dynastic conflict—some surviving as national treasures, many lost. The failure of Kenmu, paradoxically, opened the floodgates of the Southern and Northern Courts period, producing the most extravagantly scaled swords in Japanese history.