"Rainbow" and the "H" tracks were recorded in Tokyo at Avex Studios, Prime Sound Studio, JVC Victor Studios, as well as at other recording studios in Japan. "Hanabi" and "Independent" was mixed by Yasuo Matsumoto, while "July 1st" was mixed by Koji Morimoto. In order to expand her creative control, she had composed nine tracks on "Rainbow" and subsequently co-composed all the tracks from "H". "Independent" was the first song recorded for the studio album. Avex Trax director Yasuyuki Tomita and Hamasaki had discussed having a song with a baseball theme. While she was convinced by his idea, Tomita later reconsidered the idea and scrapped it. Japanese producer Dai Nagao, who had co-composed Hamasaki's album "Loveppears", thought of a similar concept and suggested the idea to Hamasaki, which she accepted. The single version of "Independent" was not featured on "Rainbow", a version of the song titled "Independent+" was included as a hidden track. This was the third time Hamasaki had included a song as a hidden track, after "Kanariya" on "Loveppears" (1999). The song discusses independence and adulthood.