Otoko Oidon is a slice-of-life manga by Leiji Matsumoto, and his first Shonen manga after spending so much time doing shōjo manga, releasing it on Weekly Shonen Magazine on May 9, 1971 until August 5, 1973. It would be the first manga to make use of elements that Matsumoto would use in his later works including the famous Star System. The manga was so successful, it won the 1972 Kodansha Publishing Award for Children's Manga. Otoko Oidon was about the adventures of a young man who was preparing himself for college.
Taking place somewhere in the 1970s in Tokyo, Japan, Bunkyo-ku, Hongo; Noboita Oyama lives a poor life as a ronin after failing his initial college entrance exams. Living in an apartment complex after losing jobs and chances to get into college, Oyama struggles everyday with life's inconveniences while also dealing with loneliness. He is constantly called a beast for his arrogant and messy behavior, but Noboita has a sympathetic soul underneath it all and despite his looks and lifestyle has a good relationship with a number of women.