"Happy Days" is Ai Otsuka's fourth single. The title track was used as background music in the Morinaga ICE BOX CM, which starred Otsuka, and as the theme of Koukousei Quiz 2004 on Nihon TV. It also contained a new b-side song and instrumental versions of both songs. It charted at Number three on the Oricon charts.
Track list
Sales Total estimate: 163,433
References
avex online (2006), Ai Otsuka Official Web Site Oricon Style (2006), Oricon Style Online