In 1967 he entered Tama Art University, and in the same year with the assistance of his peers he staged the performance piece "Self-Burial Ceremony", with which his career as an artist began.He was also active in the Japanese student demonstrations of the late 1960s, from within which he became one of the founders, and subsequently leader, of a movement known as Bijutsuka Kyoto Kaigi (Artists Joint-Struggle Council) or "Bikyoto", which sought to interrogate the institutionalized nature of art. The works of his early career tended to overlap with the activities of that movement, created as pieces questioning the foundations of art itself. With the aim of breaking through the boundaries of modernist painting, such works took a retroactive approach to the history of painting and become a process of searching for its origins. Departing from this source, Hori traced the development of painting's formation within Eastern nations and within Japan － and in so doing his own personal pictorial space took form. Meanwhile, he also began zealously developing installation and performances pieces resonating with the many issues and phenomena emerging "on the borderlines" of the society and art of "here and now". His works have been shown at numerous international exhibitions, including the 1977 Paris Biennale and the 1984 Venice Biennale.
