Check out Glinski's Hexagonal Chess, our featured variant for May, 2024.

This page is written by the game's inventor, Jose Carrillo.

Prime Ministers Chess

Prime Ministers Chess (PMC) is an adaptation of Gabriel Vicente Maura's 1968 Modern Chess (9 columns, simple reverse symmetry, symmetric castling to either side, an extra pawn, the Prime Minister (B+N) and the Bishop Adjustment Rule) to a 9x8 board.


The initial layout is identical to Maura's Modern Chess: Bishops, Knights and Rooks at the 3-leftmost and 3 rightmost squares placed just like in Orthodox Chess; the King in the middle square of the first rank (on the e-file); the Queen to the right and the Prime Minister to the left of the King. The 9 Pawns are placed on the 2nd rank.

The 9x8 board has dark squares at the corners on one of the 9-squares sides, and light squares on the other 9-squares side. It is irrelevant which side (White or Black) is playing with dark or light squares on their side.

You can play 9x8 Prime Ministers Chess on a 10x8 board (i.e. Capablanca Chess board) by covering the squares on the 'a' or 'i'-file; or on a 9x9 board (i.e. Modern Chess board) by covering the squares on the 1st or 9th rank.

Bishops start on the same color squares, but in opposite colors from one army to the next (White's Bishops may start on the light squares and the Black ones on the dark squares; or vice versa White's Bishops on the dark squares and the Black ones on the light squares). The Bishop Adjustment Rule enables the players to swap one of their Bishops to the opposite color.

While the setup described above (with Prime Minister to the left and Queen to the right of the King, and with reverse symmetry) is the original and prefered setup, the symmetry of the board allows three additional and alternate setups. The setups below are all valid Prime Ministers Chess starting layouts, for which the game can still be played under the same rules:

Note that the first alternate setup on the left also displays simple reverse symmetry, while the other two alternate setups use direct symmetry accross the board.

The code name for the main Prime Minister Chess layout (the layout same as Maura's Modern Chess) is PMC1 (or just PMC). The code names for the alternate layouts above are PMC2, PMC3 and PMC4 respectively.

When playing Over The Board (OTB), the player with the Black pieces chooses the opening layout and symmetry (reverse or direct) to use in the game. Alternately, players can choose randomly which one of the 4 setups to play by fliping a coin. Each player flips a coin to choose randomly where his/her Minister will be placed (i.e. heads = Minister to the left of the King, tails = Minister to the right of the King). The Queen will then go on the opposite side of the King.


Orthodox Chess pieces are used, plus a Prime Minister (Bishop+Knight) and a 9th Pawn per side.

Approximate Value of the Pieces on a 9x8 board

Practical Value of the Pieces (adjusted to an 8x8 board)

Kings and their Prime Ministers

Homemade Prime Ministers

Knight crowned by small Bishop, Bishop crowned with small Knight, and a crownless King.


Most Orthodox Chess rules apply, including the objective of the game, the way pieces move and capture, en passant, check, checkmate, and the various draw situations (i.e. stalemate, insufficient mating material, threefold repetition, 50-move rule). Pawns may promote to a Queen, Minister, Rook, Bishop or Knight. The Castling and the Bishop Adjustment Rules are below.


Castling in PMC is short (O-O) to both flanks of the board. During Castling the King moves 3 squares towards the Rook to castle with.

This table shows where the King and Rook end up and the notation for each type of castling.

White castles a-sideb-castlingO-ObKb1, Rc1
White castles i-sideh-castlingO-OhKh1, Rg1
Black castles a-sideb-castlingO-ObKb9, Rc9
Black castles i-sideh-castlingO-OhKh9, Rg9

Castling may only occur under the following conditions:

These rules have the following consequences:

The Bishop Adjustment Rule

Players on their turn, are allowed to convert one (and only one) of their Bishops to the opposite color square by swapping places with any piece adjacent to them. Neither the Bishop nor the piece to be adjusted with may have moved before the Bishop swap. The Bishop adjustment will count as a single turn, and a move for both the Bishop and the piece swapped with.

The Notation for the Bishop Adjustment is 'Bx <=> piece adjusting with', where x is the coordinate the Bishop is before the adjustment (i.e. Bc<=>M stands for a Bishop on the c file adjusting with the Minister).

Sample Bishop Adjustments

Prime Ministers Chess (PMC1)
Pablo Denegri (PER) - José Carrillo (PUR)
CV Game Courier, June 2008

Position after 1.e2 e4; and after 2.Bc<=>N Bg<=>M (both White and Black Adjust their Bishops on the 2nd move)


Prime Ministers Chess was proposed by José Manuel Carrillo-Muñiz, from Puerto Rico, in June 2008.

Chess Variants by the Author:

Other Presets by the Author:

Other Pages by the Author:

This 'user submitted' page is a collaboration between the posting user and the Chess Variant Pages. Registered contributors to the Chess Variant Pages have the ability to post their own works, subject to review and editing by the Chess Variant Pages Editorial Staff.

By Jose Carrillo.
Web page created: 2008-06-06. Web page last updated: 2008-06-06