"Eight Days a Week" is the first song which The Beatles took into the studio unfinished to work on the arrangement during the session, which would later become common. The song was mainly recorded in two recording sessions on 6 October devoted exclusively to this song, which lasted nearly seven hours with a fifteen-minute break in between. Lennon and McCartney tried several ideas for the intro and outro of the song. The first take featured a simple acoustic guitar introduction. The second take introduced an "oo"-ing vocal that was experimented with until the sixth take, when it was abandoned in favour of the final guitar intro. The final outro (along with unused intro takes) was recorded separately on 18 October. The final version of the song incorporated another Beatles' first and pop music rarity: the song begins with a fade-in, as opposed to the common fade-out ending. The instrumentation includes acoustic guitar, electric guitar, drums, bass and overdubbed handclaps. The fade-in and coda both include more guitar overdubs.