The Japanese-language version of "Keep Your Head Down", which was released on January 26, 2011, by Avex Trax, served as TVXQ's 31st Japanese single in Japan.

With elements of industrial hip hop and baroque pop, "Keep Your Head Down" is labeled as an SMP song, a staple genre in TVXQ's music.

The song ends with the protagonist claiming that his former lover has "[been] erased, disappeared, died" in his heart, and that she no longer ceases to exist.

[3] The song was interpreted as a diss to former members Jaejoong, Yoochun, and Junsu, who were still in a long-standing legal feud with TVXQ's agency S.M.

[4] A sample of the song's original Korean-language version was first performed by Yunho at the SM Town Live '10 World Tour in August 2010, three months before the official announcement of TVXQ's Korean comeback.

The full Korean single was released on January 3, 2011, which was accompanied by the premiere of its music video on TVXQ's official video-sharing websites.