Sadamitsu was a smith active during the late period, known primarily through joint works () produced with his contemporary Katsumitsu of the lineage. Sword reference works record three generations of the name extending through the Kakitsu era, yet Sadamitsu's existence around the Meio period could not previously be confirmed; the surviving dated of Meio 8 (1499), produced in collaboration with Katsumitsu, serves to fill that documentary gap and stands as an important reference for research into production networks.
The workmanship of the Katsumitsu-Sadamitsu collaboration displays the characteristic style of complex, compound formations. The shows with a flowing tendency (), with mixed in places; fine adheres thickly, with delicate , and stands out. The is based on open-at-the-base () , mixed with -ba and -like elements. The tempering band is broad with conspicuous undulations, while and enter frequently; adheres, and small , , and appear. The is bright and clear. Katsumitsu's particular contribution is noted as achieving a more florid and brilliant workmanship than other smiths by mixing abundant within the irregular pattern.
The designation records emphasize the powerful and splendid carvings that accompany these works -- including in superimposed carving () with , and shrine dedication inscriptions -- as distinctive features of production. The supplementary inscriptions naming the Miyake clan, a lineage that continued into the Ukita family with its base in Kojima in , further elevate these works as important sources for understanding the relationship between smiths and the warrior clans who patronized them.