Four-Fold Chess

FOUR-FOLD CHESS
by L. Lynn Smith

This game was developed over several decades of play, utilizing the entire material of four Mad Queen variant sets. The four 8x8 fields are combined to form a 16x16 pattern, which will be considered both a 16x16 field and a field of 2x2 areas in an 8x8 pattern. These 2x2 areas can be noted by placing dots of two distinct colors(white and black) on the center of each, alternating such to reflect the standard pattern of the 8x8 field. These 2x2 areas will be referred to as 'quads'.

Setup

+------+------+------+------+------+------+------+------+
|[r][r]|[n][n]|[b][b]|[q][q]|[k][k]|[b][b]|[n][n]|[r][r]|
|[r][r]|[n][n]|[b][b]|[q][q]|[k][k]|[b][b]|[n][n]|[r][r]|
+------+------+------+------+------+------+------+------+
|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|
|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|[p][p]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|
|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|[P][P]|
+------+------+------+------+------+------+------+------+
|[R][R]|[N][N]|[B][B]|[Q][Q]|[K][K]|[B][B]|[N][N]|[R][R]|
|[R][R]|[N][N]|[B][B]|[Q][Q]|[K][K]|[B][B]|[N][N]|[R][R]|
+------+------+------+------+------+------+------+------+


     P = Pawn     B = Bishop    Q = Queen
     N = Knight   R = Rook      K = King

Rules

At a turn, pieces move individually as in the Mad Queen variant, without castling or _en passant_. Or pieces may perform group movements in relation to the 'quads', under the following conditions:

There must be at least two friendly pieces in the starting 'quad', and no enemy pieces.

Players may move one or more pieces from such a position. All pieces in this 'quad' move as a unit to the same destination 'quad', and may perform such according to the power of any one of the moving pieces. With the exception that such moving units containing Pawns may only perform pawn-type moves, and those containing Kings may only perform king-type moves.

'Quads' that these piece move through must be vacant. Of course, units performing knight-type moves leap to their destination 'quad'.

Pieces of such a moving unit will occupy cells in the destination 'quad' similar to those of their starting 'quad'. For example, a piece on the upper-right cell of a starting 'quad' will move to the upper-right cell of the destination 'quad'.

Though there may be friendly pieces on the destination 'quad, pieces may not move to friendly-occupied cells of such. And those cells enemy-occupied are captured by the specific piece which moves to that particular cell. So that a piece located on a cell in the destination 'quad' which is not specifically attack by the moving pieces of a unit is not affected.

Pawns located on any cell of the second rank of 'quads' may exercise their two-step privilege, regardless of having been previously moved. If such is a 'quad' move, the cells of each of the 'quads' of this two-step move must be vacant.

Any Pawn which reaches any cell of the last rank of 'quads' may freely promote.

Kings may never be moved to an attacked position. The player is only obligated to remove a threat to their last remaining King on the field.


Let's have a few examples of 'quad' moves:


+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][k]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[p][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][b]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[P][N]|[ ][ ]|[ ][ ]|[ ][r]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[Q][K]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[B][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[P][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|[ ][ ]|
+------+------+------+------+------+------+------+------+


Though the starting cell consists of four friendly pieces, remember that it is only necessary to have at least two (and, of course, no enemy).

The forward orthogonal quad being vacant, the player is permitted to move the Pawn and any of the other three pieces to this postion. It is unable to perform a Pawn 'quad' move to the left forward diagonal 'quad' since it contains no enemy pieces to capture. But it is able to take the Bishop on the right forward diagonal 'quad', provided that at least the King is also moved in order to affect the necessary capture.

The Knight is able to perform a 'quad' move to the position two 'quad' files left containing the Pawn. It is unable to affect a capture of this Pawn since it is unable to bring along its Pawn. And it cannot bring the King because this is not a king-type move. But it may bring the Queen.

The Knight can perform a 'quad' move to the rearward position containing the friendly Pawn, but cannot bring any other piece with it. Both Pawn and King are excluded because of the type of move. And the Queen cannot move because that friendly Pawn occupies its position in this destination 'quad'.

The Queen is able to move to the 'quad' containing the friendly Bishop, but not beyond. It can bring along the Knight and/or the King but cannot bring the Pawn. It can move to the 'quad' containing the enemy Rook, but cannot bring its Pawn or King and must bring the Knight to immediately capture the enemy Rook.

The Queen is able to move to the 'quad' containing the enemy King. It also threatens the enemy King by being able to bring its Knight to this position.

The King is able to move to the three forward adjacent 'quads', and bring any of the other pieces with it except its Pawn to the left forward diagonal. It is able to move without its Pawn to the remaining adjacent 'quads' except for the position occupied by the friendly Bishop. This is because the enemy Bishop threatens the King's destination cell.

If there are no other friendly Kings, the player is obligated to remove the threat of the enemy Bishop. Either by capturing the enemy Bishop or moving the King outside its threat.

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The game is won by checkmating the opponent's last King. Keep in mind that though the player is not permitted to move a King into threat they are also not obligated to remove a threat to a King unless it is the last one.

Notes

During my naval service a rec room had several sets of the Mad Queen variant and the idea to combine them was spawned. Check out Little Mega-Chess at the Zillions of Games website for the precursor to Four-Fold Chess.

The first game only had a single King, and only the Pawns and Knights could perform multiple moves. At a turn, adjacent Pawns were allowed up to four cells, divided between the number being moved. Up to two Knights, regardless of proximity, were allowed to be moved in the same direction as a turn. These moves were simply translations on the 16x16 field.

The idea of dividing the field into 2x2 areas was inspired by the attack platform movement of the Kobayashi Maru variant of ST3D Chess. Allowing a 2x2 area of friendly pieces to move as a unit would greatly speed up the gameplay.

There was much argument about how to apply _en passant_ and castling to this game. It was finally realized that both these rules were un-necessary in this particular game. Happily they were dropped because the conditions for such were just too confusing and crippled the player's ability to logically extrapolate their position on the field.

The same was with the two-step privilege of the Pawn. Because it was difficult to keep track of previously moved Pawns, it was decided to permit this privilege based upon the Pawn being located on any cell of the second rank of 'quads'.