In Utah (and maybe in other places, but I’ve only seen it here) it’s a tradition of sorts to honk your car horn when driving through a tunnel. My father-in-law did it once, with the old, “Beep, be be beep beep” and then to our surprise, another car in the tunnel finished it off with a resounding “Beep beep!” In addition to wondering who came up with the idea of honking when driving through tunnels, I was curious about the origin of the familiar tune and rhythm that countless people use when they knock on doors, honk their horns, or end a song. I had been told the words were “shave and a haircut, two bits,” but that was the extent of my knowledge on the subject.

I found a site that explained the origin to my satisfaction, and which I’ve included below. I’m not positive it’s correct, but it sounded good enough to satisfy my curiosity.

The first recorded occurrence of the tune (with no lyrics) is in an 1899 song by Charles Hale, called “At a Darktown Cakewalk.” In 1914, Jimmie Monaco and Joe McCarthy released a song called “Bum-Diddle-De-Um-Bum, That’s It!” in which that line was featured in the last two bars of the song. In 1939, the same musical phrase was used in a tune called “Shave and a Haircut - Shampoo” by Dan Shapiro, Lester Lee, and Milton Berle. Somewhere along the line the phrase permutated into “shave and a haircut, bay rum.”

The six notes have remained the same, but over the years the phrase has become known as “shave and a haircut, two bits” (which would amount to 25 cents). Leonard Bernstein and Stephen Sondheim incorporated the tune into their “Gee, Officer Kropke” number from the musical West Side Story, and the refrain became a key plot element in the motion picture Who Framed Roger Rabbit?