Ito's solo exhibition at the Akiyama Gallery in Tokyo in 1964 of the Infinite series (see lot 53) included plastic and wooden objects with nails glued to the surfaces. In 1965 at another one-man exhibition at Gallery Crystal in Tokyo he showed cast-aluminum, everyday objects bearing what the artist called 'thorns'. Similar pieces are illustrated in Ito Takayasu, The Infinite (Tokyo: Rikuyosha, 1984), pp. 52, 53, 54.