矢岛弘一，Koichi Yajima is a Japanese screenwriter, director and actor. He was born in Chiyoda Ward, Tokyo. He is the leader of the theater company "Tokyo Mahalo". He is a member of Keidash Inc. A graduate of Nakano High School attached to Meiji University, he founded and presides over the theater company Tokyo Mahalo in 2006. He casts the right actors for each production. In November 2012, he wrote the script for the stage version of the Shochiku film Love Letter in the Drawer, starring Takako Tokiwa. In 2016, he wrote his first TV drama screenplay for The Secret Diary of Yuriko Busujima, for which he won the 35th Kuniko Mukoda Award.