Connected Chess follows the rules of standard chess, with one exception:
After each turn all isolated pieces (i.e., pieces not adjacent to any piece of either color) are removed from the board.
 
In the variant, pieces that are not adjacent to any friendly piece are removed after each turn.
 
Connected Chess requires careful development of your forces. Pieces typically must work in concert to advance across the board. In the principal game you can move a piece to a space adjacent to an enemy piece, but you should be careful when doing so because the opponent can remove your piece by isolating it. In the variant, you can capture an enemy piece by capturing its only adjacent friend, in which case you get two (or more) captures with a single move. In both the principal game and the variant it is possible to capture up to five enemy pieces in a single move. It is also possible for a piece (not the King) to commit suicide by moving to an isolated space.
 
Checkmate can be unusual. In the principal game, if the opponent King is adjacent to a friend in an otherwise empty portion of the board, you can checkmate the King by capturing the adjacent piece. In this situation, the King has no available move because reciprocal capture or moving away to an unattacked space would leave the King isolated, which is illegal. This situation is a checkmate, as opposed to a stalemate, so long as the initial capturing piece can capture the King on the next move either by direct capture or by withdrawal to a space beyond the King's reach.
 
In the illustration below, White has checkmated the Black King. The King is in check because the Rook can capture it through isolation simply by moving away. Black cannot remove the King from check because capturing the Rook would leave the Knight free to isolate the King, and because all other adjacent spaces are attacked.
 
It is possible for one King to capture the other. A King can move to a space adjacent to the enemy King as long as the enemy King is unable to attack it as a result of the isolation rule. If the moving King is in a position to move away from the enemy King on the next move, and there is no other piece that the enemy King can approach, checkmate will result. If the moving King is not in a position to remove itself from the enemy King, a strange diad may occur: The two Kings must remain adjacent to one another and yet are forbidden from capture by the isolation rule. An example of a game ending in diad can be found in the saved game called "Diad" included in the folder.
 
In the variant, you can checkmate the opponent King by attacking the only piece adjacent to it. If the opponent cannot remove the adjacent piece from attack in a way that keeps it adjacent to the King, or move the King to a space adjacent to\another friendy piece, the King will be checkmated.
 
The board may be switched with the standard Zillions chess board by selecting "Switch Piece Set" from the "View" menu. 
 
For a 4x8 "half-board" version of Connected Chess, check out Ken Franklin's Half Board Chess.