"Hikari" (Japanese: 光, "light") is a song recorded by Japanese–American recording artist Utada Hikaru for her fourth studio and third Japanese language album, Deep River (2002). It premiered on March 20, 2002 as the third single from the album in Japan. It was written and composed by Utada, whilst production and arrangement was handled by Utada, her father Teruzane Utada, and long-time collaborator Miyake Akira. The single, and a remix by Russell McNamara (under the alias PlanitB), was used as the official Japanese theme song's for the 2002 action role-playing video game Kingdom Hearts, and appeared on its original soundtrack respectively. Musically, "Hikari" is pop folk song. Lyrically, it is about mysteries in life and human activities.