"Dōshite Kimi o Suki ni Natte Shimattandarō?" (どうして君を好きになってしまったんだろう？ lit. Why Did I Have to End Up Falling Completely in Love with You??), released on July 16, 2008, is Tōhōshinki's 23rd Japanese single. Approximately two months prior to the official release of the song, a leak of the recording grossed many hits on the internet.
On July 22, 2008, Tohoshinki became the first non-Japanese Asian artist to have three number one hits on the weekly Oricon singles chart, when their single "Dōshite Kimi o Suki ni Natte Shimattandarō?" attained the number one position with weekly sales of 68,417 copies. After Tohoshinki's invitation and performance in the prestigious Japanese year-end music festival, Kōhaku Uta Gassen, the group saw a surge in sales yet again in 2009 as well as interest in the music video on online streaming sites from Japanese viewers.
Name song: Why Did I Fall In Love With You
Singer: DBSK
Sheet music: PDF , Midi
