Conversation so far:
what was Jikken Kobo?
an artistic group established for multidisciplinary collaboration on mixed-media projects, who sought to avoid Japanese artistic tradition.
what kind of projects did they produce?
During this period he wrote Saegirarenai Kyusoku I ("Uninterrupted Rest I", 1952: a piano work, without a regular rhythmic pulse or barlines).
what else did he produce?
by 1955 Takemitsu had begun to use electronic tape-recording techniques in such works as Relief Statique (1955) and Vocalism A*I (1956).

Question: was he working on his own or did he get help from others?
Self-contained rewrite: Was Tōru Takemitsu working on his own or did he get help from others?