Tsunatoshi was originally from Yonezawa in Dewa Province; his personal name was Kato Hachiro, and he used the art name Chounsai. He served as a domain smith for the Uesugi clan, later going to and taking up residence in Azabu. He died in Bunkyu 3 (1863) at the age of sixty-six. His active career is documented through dated works spanning the Tenpo era, with productions from Tenpo 9 (1838) through Tenpo 12 (1841) among those that have received designation.
Tsunatoshi's workmanship primarily followed the tradition. His specialty was a temper mixed with in , with long entering and the tending toward tightness; in addition, he produced and . The toran-flavored mode achieves a large with -, adhering somewhat unevenly, and at the . Across all styles, his forging is characteristically a tightly compacted that tends toward a -like appearance -- the plain, featureless-looking steel common in work, though in Tsunatoshi's case worked with particular density and carrying . His are noteworthy: with accompanying , , shinkurikara, , and claws, at times executed by the smith's own hand as documented by tang inscriptions stating the carvings were by the maker himself.
Tsunatoshi's extant designated works include , , and a matched pair -- the survival of which as a set makes it "especially useful reference material" in the 's assessment. His productions range from imposing of 75.5 cm with extremely deep to with elaborate carving, and one piece retains its original payment receipt addressed to the commissioning patron, providing documentary evidence of the domain smith's working practice.