Trichess follows Chess spirit and brings two evolutions (one in material and one in rule) to open the game to three players:
- A board expanded by a proportional number of squares: 64 (i.e. 2 * 32) + 32 = 96 squares; and an additional 16-piece set for the third player.
- A new prime rule, non-aggression, and a few secondary rules for managing logical developments in the game space where three players clash.
By convention, white, red and black are the three colors used to define territories (3 * 32 squares) and distinguish the players’ pieces.
On the board, White has Red on his right and Black on his left. The pieces have the same position as in Chess except one difference: for the three colors, the kings are placed on the black square, on the queen’s right, in offensive position, as is White on a 64-square chessboard.
The pieces’ movements obey the principles of Chess and their trajectories follow the curved lines on the board.
Note: the pieces go around the central obstacle, at the intersection between the three territories (white, red and black), but cannot go through it.
The pieces have the same value as in classical chess:
Pawn 1 point (1 * 8 pawns) 8 points Bishop 3 points (3 * 2 bishops) 6 points Knight 3 points (3 * 2 knights) 6 points Rook 5 points (5 * 2 rooks) 10 points Queen 9 points (9 * 1 queen) 9 points Total 39 points
The rule of non-aggression includes the notion of territoriality and the piece values: a player in numerical inferiority by at least 3 points from another player is granted a territorial semi-immunity on his 32 squares, unless that other player puts him in check.
White has lost 2 points, Red 4 points and Black 5 points. 3 points separate White from Black. Black is protected by the non-aggression rule from White. White cannot take a black piece on black territory, except if that move makes the white pieces put the black king in check.
The notion of liberation replaces that of promotion. When a pawn reaches the end of an enemy territory, it is not promoted but exchanged against one of the pieces of its color which were taken (pawn included), if there are any.
By forcing him not to play an illegal move, a player can occasionally use as a shield a piece of the next player to protect himself against a check from the previous player.
In other words:
- a black piece cannot be moved if it makes White checks Red,
- a red piece cannot be moved if it makes Black checks White,
- a white piece cannot be moved if it makes Red checks Black.
The game ends in case of a checkmate, stalemate, check and stalemate, or checkfate.
A player is in checkmate at his turn if the pieces of one other player, on their own, put him in check and forbid him any legal move (threaten his king without any escape).
There is double checkmate when the colors of two players, each independently from the other, put the third player in check and forbid him any legal move, without escape.
A player is in stalemate as in Chess when his king is not in check but he cannot play any legal move.
Check and stalemate
A player is in check and stalemate at his turn when the associated pieces of the other players put him in checkmate while no color suffices on its own to realize the checkmate. It is also called allied checkmate.
Two players are in checkfate when the third player manages to put them both in check simultaneously.
Trichess players finish the game as lord (3 points), knight (2 points), vassal (1 point) or serf (0 point).
- In case of checkmate, the player who provokes it is lord, the player who undergoes it is serf and the third player is vassal.
- In case of double checkmate, the player who undergoes it is serf and the two other players are knights.
- In case of stalemate, the three players are vassals.
- In case of a check and stalemate (allied checkmate), the player who precedes this check without preventing it is vassal, the player undergoing the check and the player after him are knights.
- In case of checkfate, the player who provokes it is lord and the two others are serfs.