A type of partner dance competition where one's partner is selected by blind draw and the music is selected by the event coordinators (cf. strictly swing, just dance). Depending on the number of contestants, there can be several preliminary heats leading up to a final heat. During preliminary heats, each competitor rotates partners several times, dancing to one or more songs with each new partner, and is advanced individually. During the final heat, competitors remain with one randomly selected partner for several songs, and are judged as a couple.

Jack and Jills emphasize the social dancing aspects of a dance, like lead/follow skills and improvisation, over choreography, since both partner and music are randomly selected.

Plain vanilla Jack and Jills assume a male leader and a female follower. Alternatively, a Jill and Jack has a female leader and a male follower, while a Jack and Jack has males for both roles, and a Jill and Jill has females for both roles.

There are several rules variations to determine who leads and who follows for Jack and Jacks and Jill and Jills:

  1. contestants register as either a leader or a follower and stick to that role for the whole competition.
  2. contestants are randomly assigned a role when they draw a partner.
  3. contestants are required to spend an equal amount of time leading and following per song or set of songs.

Yes, yes, the facts are nice and all but why Jack and Jills? Well, I can only speak from my experience in the Lindy Hop community, but in a vernacular dance like Lindy Hop, Jack and Jills reward the social dancing skills one develops by going out to clubs and events and dancing with the other regular dancers in the scene. Nobody actually uses aerials or does long breakaway routines in normal daily dancing, but it's hard to win any of the choreographed competition divisions without busting out the fancy stuff (see Minnie's Moochers for a notable exception).

That's not to say it doesn't take a great deal of skill to win a choreographed division, but that skill is to social dancing what fencing is to actually trying to kill someone with a sword. When someone wins a Jack and Jill, that's a person that you know it's going to feel good dancing with as well as look good dancing with. To win a Jack and Jill, one needs strong lead/follow, musicality, and improvisation skills. To win a choreographed division one needs a good choreographer and dancers who are good at learning choreography.

Thus, Jack and Jills promote and reward the skills one uses in daily dancing, while choreographed divisions help to innovate and push the envelope of the dance. You need both to keep the dance fresh and relevant.