Blindfold chess, also known as sans voir, is a form of chess play wherein the players do not see the positions of the pieces and do not touch them. This forces players to maintain a mental model of the positions of the pieces. Moves are communicated via a recognized chess notation.

A simultaneous exhibition or simultaneous display is a board game exhibition in which one player plays multiple games at a time with a number of other players. Such an exhibition is often referred to simply as a "simul".