He played baseball throughout his high school years, but was unable to advance to the Koshien baseball tournament.
Ichinose has even participated Koshien, the most famous Japanese High School Baseball Championship.
An excerpt from one such letter, written in hiragana and with an Osaka dialect, reads, “Dear dumb police officers. Don't tell a lie. All crimes begin with a lie as we say in Japan. Don't you know that?” Another taunting letter was sent to Koshien police station.
They are organized by the Japan High School Baseball Federation in association with Mainichi Shimbun for the National High School Baseball Invitational Tournament in the spring (also known as "Spring Kōshien") and Asahi Shimbun for the National High School Baseball Championship in the summer (also known as "Summer Kōshien").
Several professional baseball players first made their mark at Kōshien, including Eiji Bandō, Sadaharu Oh, Koji Ota, Suguru Egawa, Masumi Kuwata, Kazuhiro Kiyohara, Hideki Matsui, Daisuke Matsuzaka, Yu Darvish and Masahiro Tanaka.