The Collegiate Shag (or "Shag") is a partner dance done primarily to uptempo swing and pre-swing jazz music (185-200+ beats per minute). It belongs to the swing family of American vernacular dances that arose in the 1920s and 30s. It is believed that the dance originated within the African American community of the Carolinas in the 1920s, later spreading across the United States during the 1930s. The shag is still danced today by swing dance enthusiasts worldwide.
In the 1930s "shag" became a blanket term that signified a rather large family of jitterbug dances (swing dances) that all shared certain characteristics. The most notable of these characteristics are (1) a pulse that's consistently held up high on the balls of the feet (a.k.a. a "bounce" or "hop" to match every beat in the music) and (2) footwork with kicks that reach full extension on the off-beat (even beats) rather than the on-beats (odd beats) as with most other dances that were popular at the time. Dance instructors from the swing era often grouped the different shags into three rhythmic categories: single rhythm, double rhythm, and triple rhythm shag. The different names are intended to denote the number of 'slow' steps (e.g., a step, hop combination) performed during each basic. The slow steps were then followed by two 'quick' steps (e.g., a step, step combination).
Today, shag enthusiasts and swing dance historians also recognize an additional shag rhythm that has come to be known as "long double-shag". This rhythmic variation is identical to double-shag except that it has four quick steps rather than two. It has been traced to Charlotte, NC, at least as far back as 1936, where it co-existed with the triple and single-rhythm variations. It is commonly believed that double-rhythm shag evolved somewhat later than the others, originating in either New York or New Jersey in the mid-1930s. And, though double-shag is the most popular form of collegiate shag today, single-rhythm shag is believed to have been the dominant rhythmic pattern during the swing era.
Described below is double-rhythm shag, which uses a "slow, slow, quick, quick" pattern. And unlike the other three rhythmic patterns, which all have eight or sixteen counts in their basic, the double-rhythm basic has six counts.
The basic step is danced in a face-to-face ("closed") but offset position (i.e., the lead and follow are chest to chest, but their orientation to one another is offset in such a way that the feet are not toe-to-toe but alternate like the teeth of a zipper). Partners stand close, with the lead's right hand positioned on the follow's back. The follow's left arm then rests either on the lead's shoulder or draped around his neck.