Blindfold chess

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.

Blindfold chess was considered miraculous for centuries but now there is greater recognition of people who can keep track of more than one simultaneous blindfolded game. In simultaneous blindfold play, an intermediary usually relays the moves between the players.