Minakami attended Keiō High School and played on the school's baseball club. While attending Keio University, he was inspired by the works of Kyōka Izumi and by a newly appointed professor, Kafū Nagai, who was also the founder of the literary magazine Mita Bungaku, launched in 1910.
Minakami was an athlete at Keiō High School, playing baseball for his school. At Keio University, he drew inspiration from Kyōka Izumi's work and a professor named Kafū Nagai, who also started the literary magazine Mita Bungaku in 1910.