After graduating from terakoya (a private elementary school during the Edo period) called Baisendo (Baisen Primary School, later Sakuragawa elementary school, and the present-day Onarimon elementary school in Minato Ward), Koyo went to Tokyofu Daini Junior High School (soon became Tokyofu Junior High School after merging with Tokyofu Dainichi Junior High School; present-day Hibiya High School, Tokyo).
寺子屋・梅泉堂（梅泉学校、のち港区立桜川小、現在の港区立御成門小学校）を経て、府第二中学（すぐに府第一中と統合し府中学となる。現在の東京都立日比谷高等学校）に進学。