Koshimichi was born in 2004 in Hiroshima City, Hiroshima Prefecture, before playing for Satominami FC (Hiroshima Municipal Kawauchi Elementary School), then Hiroshima Junior Youth (Hiroshima Municipal Jonan Junior High School), and then Hiroshima Youth (Yoshida High School).[2]
Club career
Koshimichi started his career with Sanfrecce Hiroshima after playing for their youth academy.[3]
Before the 2023 season, Koshimichi was named as a player to watch for Sanfreece Hiroshima, along with Shuto Nakano.[4]
Koshimichi made his debut for Sanfreece Hiroshima on February 26, coming on in the 90th+1st minute for Hayato Araki.[5]
International career
Koshimichi has been called up to represent Japan at youth level.[6]