Towards the end of the game, in consequence of the combined action of the pawns, and the distances to be traversed, a knight’s value is greatly reduced.
We have found it advantageous to exchange a knight for a bishop towards the middle of the game.
The great object of the game is by combined action to suddenly checkmate one adversary. His pieces, though not removed from the board, are then dead, and cannot return to life until the checkmate is removed.
They cannot be taken, but are practically useless, except as offering the shelter of inert matter to partner’s pieces.
One partner having been checkmated, the antagonists concentrate their attack upon the remaining one, with the enormous advantage of having two moves to his one!
Only, therefore, by making desperate sacrifices to release his partner from checkmate can the non-checkmated one hope to save the game, except his adversaries should stalemate him, when it is drawn.
While one is checkmated the adversaries may move in and out amongst his pieces with impunity, and should adversaries’ kings do so, they are not exposed to check, as the pieces are considered dead.
This is most important, as it enables the adversaries, having once secured checkmate, to render it permanent by pieces of lesser value, withdrawing important pieces to fight against remaining partner, who, although combating single-handed, may be numerically superior to both.
It is lawful to open adversary’s checkmate for the purpose of capturing any of his pieces, who by that means are returned to life. But it should be borne in mind that if in doing this stalemate is given, the game is drawn.
Though the adversary may at any time open checkmate, he cannot in the same move take a piece, but his partner may do so, and he may close the checkmate again at his discretion when it comes to his turn. (See [Rule 4].) The game is only won by both partners being checkmated.