Musical History 2

2006–2007: Breakthrough success

On May 23, 2006, SM Entertainment revealed the thirteenth member Kyuhyun, who was discovered through a singing competition in 2005. They released their single "U" online for free download on May 25, 2006 in their official website. "U" had over 400 thousand downloads within five hours of release and it ultimately exceeded 1.7 million downloads, crashing the server.[15][16] The physical single of "U" with a total of three tracks was released on June 6, 2006, eventually selling over 81,000 units by the end of the year.[17] During this time, an official fanclub was created for the group, E.L.F., an alphabetism derived from the phrase "Ever-lasting Friends." Super Junior's official color became pearl sapphire blue.[5][d]

"U" yielded number-one spots for five consecutive weeks on two of Korea's top music programs for the first time in the group's career.[18] "Dancing Out," their first promotional single for SM Town's annual summer album, was released on July 20, 2006 and met similar success, grabbing two single awards in August.[19] Super Junior collected over seven awards in five of South Korea's top music award ceremonies as 2006 came to a close, winning Best New Group and popularity awards.

Due to busy individual schedules, Super Junior promotional activities remained inactive in the latter months of 2006 except for Super Junior-K.R.Y., Super Junior's first official subgroup. The ballad-singing trio debuted on November 5, 2006, with the performance of "The one I love", the theme song for the tvN television drama Hyena (하이에나).[20] A second subgroup arrived in February 2007 called Super Junior-T. The trot-singing group released their first single "Rokuko" in February 23, 2007 and made a debut performance two days later.[21] That following March, Yesung, Kang-in, Sungmin, Donghae, Ryeowook, and Kyuhyun participated in an original soundtrack for the first time, singing the opening and ending themes "Success" and "H.I.T" for the Korean miniseries, H.I.T.