Yagi Kazuo was born in Kyoto in 1918. He was the eldest son of the ceramic artist Isso Yagi. After graduating from the sculpture section of the Kyoto Municipal Arts and Crafts School, he became a student at the Ceramic Laboratory in Kyoto. He joined the Clay Sculpture Association of Japan and was selected for the 2nd Nitten exhibition for the first time. In 1946 he took part in establishing the Young Ceramic Artists Group. In 1948, along with Suzuki Osamu and Yamada Hikaru, he established the avant-garde group Sodeisha as a vehicle for expanding the expressive possibilities of clay. He became the standard bearer for new art in postwar Japan.
Yagi Kazuo was the first artist to incorporate the black ware method into contemporary ceramic art. He called this new work “object ware”. Black ware is made by burnishing the surface of the clay form and firing it at a low temperature in a smoky atmosphere to allow it to absorb carbon. Despite the limitations of the medium, he was attracted to black ware because it was possible to retain the original tactile quality of the clay and emphasize the materiality of his art.