Yamato no Kami Yasusada, whose family name was Tomita and common name Sobei, was traditionally regarded as originating from Province; however, recent research has clarified that he emerged from the Kishu Ishido group of Province. His workmanship shares points in common with Izumi no Kami Kaneshige: both and tend to show good clarity, and the construction and finishing of the are likewise similar. He is traditionally said to have been a student of Yasutsugu, yet his workmanship is closer to that of Kaneshige, and within the corpus of -period -to his style shows affinities to Kotetsu.
Yasusada's characteristic manner is defined by a foundational quality -- a wet, lustrous appearance -- with mixed into the temper, accompanied by and . His is a tightly packed with fine and a clear, bright appearance. The displays variation through the inclusion of angular and , with deep , well-adhering , and a bright . Distinguishing features include the angularity seen in the peaks and valleys of the , the comparatively steeply formed , and the wide . In comparison with Kotetsu, a conspicuous tendency toward areas of and a nigore effect stand out as points of interest. His tends to show a shallow, moist quality turning back in a rounded manner.
Yasusada's blades frequently bear gold-inlaid () cutting-test inscriptions, often by Yamano Ka'emon Nagahisa and other notable testers, attesting to the esteem in which his swords were held as practical weapons. His and are sound works of the -to period, displaying the clarity and controlled vigor that mark the best of the Ishido tradition.