The movie was made as the first feature of the Committee of the Four Knights, a group founded by four of Japan's greatest directors: Akira Kurosawa, Keisuke Kinoshita, Masaki Kobayashi and Kon Ichikawa. According to a interview with Ichikawa, they wanted their first picture to be a hit. When this film told a story deemed too depressing and was subsequently a failure with audiences, the group disbanded and never made another film. The movie's failure also contributed to Kurosawa's suicide attempt one year later.
The drawings shown toward the end of the film weren't by Akira Kurosawa. He usually used his own paintings, but he didn't think they'd feel right or childish enough, so he had some children draw some paintings that are the ones ultimately shown in the finished picture.
Shooting began on April, 23rd, 1970, and was shot in about a month, which is an incredibly short period of time for a Kurosawa picture, given the facts that a) Kurosawa was a perfectionist, and b) his prior film, Red Beard (1965), took two years to go through all the phases involved in finishing a motion picture.