3121 is the first track on Prince’s 31st studio album 3121. In 2008, a 2007 live recording of the track was included as the first track on Prince’s fourth live album Indigo Nights, incorporating renditions of The Entertainer (Scott Joplin’s 1902 composition), Alexander’s Ragtime Band (Irving Berlin’s 1911 composition), Music! Music! Music! (by Bernie Baum and Stephan Weiss, from Teresa Brewer’s 1949 single Music! Music! Music!), and Prince’s own D.M.S.R. (from 1999).
Basic tracking took place on 19 November 2004, during a three-and-a-half hour session with Michael B. on drums and Sonny T. on bass at Paisley Park Studios in Chanhassen, Minnesota that also yielded From The Lotus..., ...Back 2 The Lotus, Colonized Mind, Love Like Jazz, Wall Of Berlin, Planet Earth, Guitar, a song titled Shameless as well as two or three others. A tape photographed in Prince’s vault at Paisley Park Studios lists Wall Of Berlin as 19 November 2004, which alludes this is the exact date for all of the songs in this sessions. In an August 2006 interview, Michael B. confirmed the recording date and said [they recorded] eleven or twelve tracks in three and a half hours that night. Much like Ripopgodazippa, 3121 was based around a bass line and a beat created by Sonny T. and Michael B. during that session, although they are uncredited.
Prince allegedly wrote the song inspired by the 3121 address of the house, in the week he hired it, so it is likely an early version of the song was recorded in October 2004.
Prince wore a jacket with the "3121" logo (as on the album cover) when performing at the 36th NAACP Image Awards on 19 March 2005, and his rented mansion in Los Angeles at the time was at 3121 Antelo Rd., the address of which inspired the track’s title. It was included as the first track on a late 2005 configuration of 3121, where it remained for release.
Of note is that the intro of 3121 contains some disguised spoken words that say "From the lotus flower..." also used on ...Back 2 The Lotus (although not on From The Lotus...) and ends with the phrase "It’s going down y'all, like the wall of Berlin", all referring to songs recorded during the same session.
The "wall of Berlin" is a reference to the Berlin Wall, which divided the cities of West Berlin and East Berlin (and the countries of West Germany and East Germany, respectively) until its fall in 1989.