Root Letter is a mystery visual novel developed by Kadokawa Games for PlayStation 4 and PlayStation Vita. The game follows a 33-year old man named Nakamura Takanori investigating the disappearance of his old pen pal from high school, a woman named Fumino Aya. After loosing contact with Aya more than 15 years ago, Takanori happens to discover Aya's last letter she sent him that contains a farewell message and a confession to committing a murder. Now Takanori must go to Aya's home town, question her friends from high school, and use her old letters to find clues behind what happened 15 years ago.
Several former Konami employees who had previously worked on the Love Plus franchise, including character designer Mino Taro, developed Root Letter. The game was planned to be the beginning of a series of visual novels called Kadokawa Game Mystery. Root Letter also introduces the cast of fictional actors and actresses that will star in all of Kadokawa's mystery games, similar to Laura Harris and Osamu Tezuka's Star System.
Root Letter was released in Japan on June 16, 2016 and was published the same year in North America and Europe by pQube. A port for the PC was later released by Kodokawa Games in 2017.