Domination

A knight in the center touches eight squares. On the rim it touches four. In the corner it touches two. Its mobility collapses as it approaches the edge, and unlike a bishop it cannot escape in one move: every hop is short, and it can never lose a tempo. Those three facts are the whole theory of dominating a knight.

That is why rook versus knight, a book draw when the knight stands beside its king, becomes a win when the knight is separated from it. King and rook working together can herd the horse toward the rim, and the rook takes away whole ranks of escape squares from a distance while the king closes in. The one thing you must not do is chase with the rook alone: that only teaches the knight the way home.

Our drill “Rook vs Knight: The Stranded Horse” is the pure version. There is one commandment for the defender (keep the knight next to the king), and if he has already broken it, there is a hunting method for you.

A bishop is a long-range piece, so it is dominated differently: not by taking its squares one at a time, but by cutting its diagonals. Block the long diagonal it needs and a bishop can become a spectator without ever being attacked.

The reverse case is prettier, and it is the fastest way to feel what domination means. In our drill “Cutting the Knight Off with the Bishop”, a knight on h5 has exactly four moves: f4, g3, f6 and g7. One bishop move, Be5, covers all four at once. The knight has not been captured or attacked, it has simply been switched off, and the rest of the position is played a piece up. Only that move wins.

The same mechanism in a different shape is “Good Bishop vs Bad Knight”: the bishop stands on the diagonal that escorts one pawn and guards the other wing's entry square, while the knight, needing four tempi to cross the board, cannot serve both flanks.

Not every piece can be dominated, and knowing when to stop is worth as much as knowing how to hunt. Rook versus bishop with no pawns is a draw, because the defending king can reach the corner whose color the bishop does not control, and there the bishop always has the interposition and the stalemate trick. The rook can dominate any square on the board except the ones it needs.

A knight beside its own king is likewise indominable: the two defend each other, and the rook can circle for fifty moves without loading a real threat. Togetherness is the whole defense.

So the practical rule cuts both ways. As the attacker, look for the piece that has wandered: separation is the precondition of domination. As the defender, keep your pieces holding hands and head for the corner that suits your bishop, and the position that looks lost is a fortress.