"Hikari" was written and composed by Utada, whilst production was handled by Utada, her father Teruzane Utada, and long-time collaborator Miyake Akira. The song's instrumentation consists of keyboards and programming handled by Kawano Kei, synthesizers from Tsunemi Kazuhide, and an acoustic guitar from Akiyama Hironori. The song was recorded by Ugajin Masaaki and mixed by Goh Hotoda in 2001 at Bunkamura Studio, Shibuya, Tokyo. It was released as the third single from her fourth studio and third Japanese language album, "Deep River" (2002). Since then, the song has been remastered and re-released twice; the first on April 1, 2004, and the second time on December 9, 2014 for Utada's first greatest hits album "Utada Hikaru Single Collection Vol. 1" (2003).