The Dawn: How Swordsmithing Forged the Origins of Tosa Blades

The technical roots of Tosa forged blades stretch all the way back to the late Kamakura period. The story is said to have begun in 1306 (the first year of the Tokuji era) when a group of swordsmiths (katanakaji) led by Gorozaemon Yoshimitsu migrated from Yamato Province (modern-day Nara Prefecture) to Tosa Province (modern-day Kochi Prefecture). In an era of constant warfare, they crafted armor and swords, laying the groundwork for the region's advanced forging techniques.

Later, from the Sengoku to the Azuchi-Momoyama period, a full-fledged industrial base began to form. The "長宗我部地検帳" (Chosokabe Chikencho), a land survey conducted in 1590 (the 18th year of the Tensho era) by Chosokabe Motochika, who had unified Tosa, records that there were as many as 399 blacksmiths in his domain. This reveals that blacksmithing was already a major, established industry even before the dawn of the Edo period.

Moreover, tradition holds that when Chosokabe Motochika joined Toyotomi Hideyoshi's campaign in Odawara, he brought back skilled swordsmiths from Sado Island. This is thought to have been a key factor that spurred technological innovation in the region.

During this era, the primary products were still weapons and swords. Their character was that of tools for war, rather than tools for the daily lives of common people.

The Edo Period: A Pivotal Moment Forged by Domain Reforms

The catalyst that directly sparked the dramatic evolution of Tosa forged blades, shifting their focus from weaponry to everyday tools, was a series of domain-wide reforms in the early Edo period. In 1621 (the 7th year of the Genna era), the Tosa Domain, facing severe financial hardship, launched a large-scale initiative known as the 'Genna Reform.' This movement was powerfully spearheaded by Nonaka Kenzan, a chief retainer of the Tosa Domain.

Nonaka Kenzan's policies were twofold: increasing rice production by developing new agricultural fields and actively leveraging the vast forest resources that covered most of the domain. This massive, government-led development project created an unprecedented surge in demand for bladed tools—hoes (kuwa) and sickles for farming, and the axes (ono) and hatchets (nata) essential for forestry.

This explosion in demand presented a golden opportunity for Tosa's blacksmiths. To meet the soaring demand within the domain, they competed to hone their skills, dramatically improving both production volume and quality. It was this period of intense technical refinement that truly built the industrial foundation for Tosa forged blades that endures to this day. This top-down policy approach, driven by the domain government, ultimately sparked a wave of innovation among the artisans, creating an 'industrial cluster' that concentrated both demand and craftspeople in a single region.