Nobukuni Yoshisada

Nobukuni Yoshisada was the twelfth-generation heir of the Nobukuni school (founded in the Nanbokucho period by the smith Nobukuni, a student of Ryokai of the Rai school) and the founder of the Chikuzen Nobukuni school. Following the fall of the Ajimu domain in 1582, he came into the service of the Kuroda house under Kuroda Yoshitaka and then Nagamasa, campaigning with them in the 1592 Korean invasion before relocating from Buzen Province to Chikuzen Province in 1602 (Nagamasa having received Chikuzen's 520,000-koku domain after the Battle of Sekigahara). He died on September 1, 1640.

He is documented in the Wikipedia article "Nobukuni Josazaemon Yoshisada" and left behind a genealogical record titled "Nobukuni Hajime no Keizu Daidai Soshi-tsuki no Koto" — an invaluable primary source for Nobukuni school history.

In Chikuzen, Yoshisada and his son Yoshimasa established the Chikuzen Nobukuni school in Hakata. The school's blades are characterized by powerful, weighty construction suited to Kuroda warrior tastes — with frequent kinsuji in the hamon, vigorous nie, and a robust, unrefined quality admired by retainers of the domain. The Fukuoka City Museum has held dedicated exhibitions on the Chikuzen Nobukuni smiths, reflecting the school's continuing historical significance.

Yoshisada is classified as Josaku and stands as the pivotal figure who transplanted the ancient Nobukuni lineage to Kyushu, where it flourished through successive generations of the Chikuzen Nobukuni school.