安永天明の飢饉期

The An'ei (1772–1781) and Tenmei (1781–1789) eras coincided with Japan's worst natural disasters of the Edo period. The catastrophic Tenmei Famines (1782–1787), compounded by the massive eruption of Mt. Asama in 1783, killed over a million people and devastated the rural economy. Sword commissions dried up as daimyō finances deteriorated, forcing many smiths to abandon sword production entirely or pivot to agricultural tools. Yet this era of hardship also incubated the intellectual revolution that would reshape Japanese swords: Suisinshi Masahide (1750–1825), working through the Tenmei hardship years, was developing his comprehensive study of Kamakura and Nanbokuchō kotō. His eventual publications—Tōken Jitsuyō-ron and other treatises—launched the shinshintō movement's foundational philosophy of returning to ancient techniques. The era also featured the Tanuma Okitsugu political period (1772–1786), which prioritized commercial enrichment over warrior values, accelerating the shift in sword patronage toward wealthy merchants. The Tenmei Rice Riots of 1787 and subsequent Kansei Reforms returned austere warrior ideology to fashion, creating the cultural context in which Masahide's ancient-revival arguments would find a receptive audience. Sue-shintō blades of this period are often considered inferior to earlier Edo masterworks, but they faithfully document the social pressures of their troubled time.