"Castle Imitation", the theme song for the PlayStation 2 role-playing game, Breath of Fire: Dragon Quarter. In January 2003, the documentary television program, Artist Document Kami ga Maioriru Shunkan: Chihiro Onitsuka 22 sai no Sugao was broadcast on NHK. Onitsuka released a single "Sign". To promote the single, she appeared several television variety shows, including "Mezamashi TV" and "Waratte Iitomo!". The single peaked at number four on the Oricon Weekly Singles chart, becoming Onitsuka's highest-charting song on the chart. Her follow-up single "Beautiful Fighter" was released in August 2003. It was commercially less successful than her previous singles, selling only 36,000 copies. However, it peaked at number nine on the Oricon Weekly Singles chart. On September 10, 2003, Onitsuka announced she would take a hiatus until the end of the year to undergo a surgery to remove polyps and recover from her poor throat condition. Shortly before the announcement, she finished the recording of "Ii Hi Tabidachi, Nishi e", a cover of Momoe Yamaguchi. The song was released in October 2003 and sold 83,000 copies, making it her sixth best-selling song. The song served as the theme song to West Japan Railway Company's Discover West campaign. In November 2003, she released "Watashi to Waltz o", which served as the theme song to the third season of Trick, as well as her previous hits "Gekkō" and "Ryūseigun". The song became her last single under EMI Music Japan. 2004–2006: "Sodatsu Zassō" and two-year hiatus In March 2004, the box album titled Single Box was released without her approval. It managed to sell approximately 3,000 copies and entered on the Oricon Weekly Albums chart at number one hundred and six. Her fourth studio album was set to be released in the same year, but the album was cancelled and substituted by the release of the box album. On June 18, 2004, she transferred to Sony Music Artists as a production label and A&M Records as a record label. In September 2004, she performed "King of Pain", "Smells Like Teen Spirit", and premiered her original song "Sodatsu Zassō" at Sweet Love Shower 2004. The performance gained great public attention as she appeared in hard rock style costume, breaking down her previous pure image. The song was released in October 2004 and peaked at number ten on the Oricon Weekly Singles chart. After the release, she announced that she would put her career on hiatus