Influenced by their label mate BoA, TVXQ crossed over to the Japanese music industry in 2005, and released their debut Japanese studio album Heart, Mind and Soul in March 2006.

However, sales improved for their second Japanese album Five in the Black (2007), which peaked at number ten on the Oricon.

In between their early J-pop endeavors, they issued two more Korean albums Rising Sun (2005) and "O"-Jung.Ban.Hap.

It achieved a double platinum certification from the RIAJ after only a month of release.

In September, the duo issued TVXQ's fifth Japanese album Tone, which became TVXQ's first regular studio album to top the Oricon, breaking a sales record previously set by Bon Jovi.