One of the basic forms of this game is to choose absolutely anything and allow the target individual to ask questions with a possible Yes/No answer. The game is played with one player as the victim and with everyone else forming an ad hoc committee to provide replies.

The most important feature is that questions must always be answered with a Yes or No reply. Questions asked that cannot be answered in this way must be answered only to the effect that no reply is possible. If the victim wishes to pursue questioning in the same area, then they will need to reword their request.

The existence of the committee means that obscure or difficult questions can be considered by everyone involved and a consensus reply delivered. More often than not, however, borderline questions are answered by factions of the committee with both a Yes and a No - providing very little assistance to the victim.

The victim can make guesses at who or what they are at any time, representing another Yes/No question. The game ends when the victim announces their identity correctly.

Variations on the game involve a set limit to the number of questions that can be asked, or for the victim to be required to direct questions at specific individuals who must answer without assistance. This opens up the possibility that a difficult question aimed at the wrong individual can lead the victim miles off course.