Four-Player Chess/How to play?

Board and pieces
Four-player chess is played on an 8x8 board that is extended by three rows of eight squares on each side. In other words, it is a 14x14 board with the 3x3 corners removed. The board has 14 files, assigned the letters a-n, and 14 ranks, numbered 1-14. The game is played with four regular sets of chess pieces, each of a different colour. The colours used throughout this book are red, blue, yellow and green.

Players
The game is played with four players, each with their own set of pieces. The players will hereafter be referred to as Red, Blue, Yellow and Green, corresponding to the colour of their respective sets of pieces. Red is the first player and always makes the first move. Therefore, the standard board orientation is from Red's perspective, i.e. Red is shown at the bottom. The second player is Blue, who is seated on the left side of Red. Yellow is the third player and is seated across from Red. The last player is Green and is seated on the right side of Red, across from Blue. The game continues in clockwise order, i.e. Red, followed by Blue, followed by Yellow, followed by Green and then Red again etc.

Initial position
Looking from each player's perspective, the pieces are arranged the same way as in regular chess, with the exception that for Blue and Green the king and queen are swapped. That is, the rooks go in the corners, the knights are placed next to the rooks and the bishops are placed next to the knights. All kings are placed on light squares and all queens are placed on dark squares. The pawns are placed in front of the pieces. The board should be oriented such that the lower right square of the 8x8 central part of the board is a light square, when viewed from Red's perspective, just like a regular 8x8 chess board. (If one would imagine a complete 14x14 board, the "n1" square on the bottom right should be a light square.)

In terms of files and ranks, Red's pieces are placed on the first rank and the pawns on the second rank, Yellow's pieces are placed on the 14th rank and the pawns on the 13th rank, Blue's pieces are placed on the a-file and the pawns on the b-file and Green's pieces are placed on the n-file and the pawns on the m-file.

Rules
There are two main variants of four-player chess as found on the internet chess server Chess.com: Free-For-All (FFA) and Teams. In the FFA variant each player plays on his own and in the Teams variant the players across from each other form a team. Pieces move the same way as in regular chess and castling and en passant captures are also the same.

Teams

 * Red and Yellow form a team and Blue and Green form a team.
 * A teammate's pieces cannot be captured.
 * Players are allowed to make moves that put their teammate in check.
 * Pawns promote to queens on the 11th row from each player's perspective.
 * Checkmate only takes effect when a player's turn is reached, allowing a player's teammate to intervene.
 * The first team to checkmate one of the opposing team's players wins the game.
 * The game is a draw in case of stalemate, insufficient material, three-fold repetition or the 50-move rule.
 * The standard time control is 1 minute with a 15-second delay each move.

Free-For-All (FFA)

 * The goal is to score the highest amount of points of all players. Points can be earned in the following ways:
 * Checkmate (+20)
 * Capturing active pieces:queen (+9), rook (+5), bishop (+5), knight (+3), pawn (+1), promoted pawn as queen (+1)
 * Checking two players simultaneously (+5)
 * Checking three players simultaneously (+20)
 * Pieces become inert when a player is eliminated and they no longer award any points when captured.
 * Pawns promote to 1-point queens on the 8th row from each player's perspective.
 * The game ends when three players have been eliminated. The player with the most points wins the game. (Note that this is not necessarily the last remaining player.)
 * When a player resigns or times out, leaving two or more active players on the board, that player's king remains "alive" and is still worth +20 to whoever can capture it. The last remaining player will be given +20 for each king of all resigned or timed out players that is still on the board.
 * In case of stalemate, insufficient material, three-fold repetition or the 50-move rule, the remaining players receive +10 points each.
 * The standard time control is 1 minute with a 15-second delay each move.