Yoshihara Jirō is one of the most important figures in postwar Japanese art. Yoshihara had developed a dynamic artistic career, starting as a self-taught yōga (Western-style painting) artist. After experimenting with various modernist styles, Yoshihara had eventually matured as a gestural abstract painter in the early 1950s. In the 1960s, Yoshihara conceived his signature Circle series paintings, comprising the seemingly calligraphic circles against a monochrome background, which have received great attentions in and out of Japan. Besides his individual artistic activities, Yoshihara notably founded the Gutai Art Association, the legendary avant-garde artists’ group in 1954. He was active as its leader, artist and manifestor, organising experimental events and forging international networks with artists, critics and curators through the Gutai journals.