Game Rules

Reconnaissance blind chess (RBC) is actually a family of games. For this competition we will focus on one variant, which we will refer to as reconnaissance blind chess (RBC) for simplicity.

Reconnaissance blind chess (RBC) was intentionally designed to keep the game as close to chess as possible while adding an appropriate amount of uncertainty and explicit sensing. It is like chess with the following core differences:

  • A player cannot see where her opponent's pieces are.

  • Prior to making each move a player selects a 3 x 3 square of the chess board. She learns of all pieces and their types within that square. The opponent is not informed about where she sensed.

  • If a player captures a piece, she is informed that she made a capture (but she is not informed about what she captured).

  • If a player's piece is captured, she is informed that her piece on the relevant square was captured (but she is not informed about what captured it).

  • There is no notion of check or mate (since neither player may be aware of any check relationship).

  • A player wins by capturing the opponent's king or when the opponent runs out of time. In this competition, each player begins with a cumulative 15-minute clock to make all her moves.

  • If a player tries to move a sliding piece through an opponent's piece, the opponent's piece is captured and the moved piece is stopped where the capture occurred. The moving player is notified of the square where her piece landed, and both players are notified of the capture as stated above.

  • If a player attempts to make an illegal pawn attack or pawn forward-move or castle, she is notified that her move did not succeed and her move is over. Castling through check is allowed, however, as the notion of check is removed.

  • There is a "pass" move, where a player can move nothing.

  • There are no restrictions on the computational resources employed by participants' bots.

  • There is no limit to team size and team members may come from different institutions.