Tadamasa, called Shozaemon, is the founding hand of the Akasaka school of iron openwork tsuba, a line said in the records to have moved from Kyoto to the Akasaka district of Edo at the start of the Edo period and to have flourished there to the end of the bakufu. He is named with the makers of Kyoto, Owari and Higo as one of the celebrated workers of the pierced iron guard. The first three generations, the so-called old Akasaka or upper three generations (1st Tadamasa, 2nd Tadamasa, 3rd Tadatora), are all unsigned; in-mei work begins only with the fourth generation Tadatoki around Genroku, with the signature Bushu-ju Akasaka Hikojuro Tadatoki saku, and the legitimate line thereafter took the name Tadatoki to the ninth generation. The name Tadamasa was carried by both a first and a second generation, both called Shozaemon; by a genealogy the descendant Tadatoki submitted to the bakufu in the Bunsei era, the first Tadamasa died in Meireki 3 (1657) and the second in Enpo 5 (1677). All accepted work of these upper generations is unsigned, so attribution rests on the iron, the openwork composition and a small set of construction features.

Tadamasa, called Shozaemon, is the founding hand of the Akasaka school of iron openwork tsuba, a line said in the records to have moved from Kyoto to the Akasaka district of Edo at the start of the Edo period and to have flourished there to the end of the bakufu. He is named with the makers of Kyoto, Owari and Higo as one of the celebrated workers of the pierced iron guard. The first three generations, the so-called old Akasaka or upper three generations (1st Tadamasa, 2nd Tadamasa, 3rd Tadatora), are all unsigned; in-mei work begins only with the fourth generation Tadatoki around Genroku, with the signature Bushu-ju Akasaka Hikojuro Tadatoki saku, and the legitimate line thereafter took the name Tadatoki to the ninth generation. The name Tadamasa was carried by both a first and a second generation, both called Shozaemon; by a genealogy the descendant Tadatoki submitted to the bakufu in the Bunsei era, the first Tadamasa died in Meireki 3 (1657) and the second in Enpo 5 (1677). All accepted work of these upper generations is unsigned, so attribution rests on the iron, the openwork composition and a small set of construction features.