Last week, I shared some of my thoughts on endgame mastery for improving chess players. I mentioned that learning the ending for Knight and Bishop against lone king could wait, since it occurs infrequently over the board. That’s still my opinion.
For stronger improvers, say ELO 1800 and above, there is some benefit in working through the mate. If you do not know the mate, please get out a chessboard for this. Don’t work through it in your head.
Depending on where the lone king is located on the board, it can take as many as 35 moves to achieve mate. So, with the 50-move rule, that means your technique has to be spot on for this. Your play has to be precise. One inaccuracy can mean a draw under the 50-move rule. That’s one of the important the benefit of learning this mate. You have to be able to calculate precisely. Another important benefit. You must keep your pieces coordinated.
GM Karsten Mueller does an excellent job walking viewers through this mate in his first DVD for ChessBase on the endgame. I’m going to break this down into the same stages as GM Yuri Averbakh in his classic book, Chess Endings: Essential Knowledge. This is a small, lucid book on endgame play from the 1960s. I’m going to use his positions, too.
Let’s start with the simplest case. The lone king is already in a correct corner of the board. That’s the corners with the same color as the bishop. The bishop and knight together control four important squares in the diagram below. The white king then comes forward to shoulder the enemy king towards the corner. From this point, if black plays precisely, mate takes nine moves.
Most players beyond the weakest novices know that the mate is only possible in a corner controlled by the bishop. As the endgame approaches, they’ll likely run to corner opposite that of the bishop. Thus, you need to know how to force the king from a “wrong” corner to one controlled by the bishop. Averbakh doesn’t name the technique. GM Karsten Mueller calls this the “W-maneuver.” That’s a helpful mnemonic that describes how the knight moves across the board.
Keep in mind that it is the knight moves that will spoil your mate quickest. That’s because the knight trots while the bishop can move more quickly.
With best play by black, this adds eleven more moves to the mate.
When the endgame begins on the edge but the lone king is in the middle, you might need to give the lone king some space. You also need to lose a tempo or two.
The worst case is the lone king away from the center of the board. The process begins by driving the king to the edge of the board. From there, the mate continues, depending on where along the edge the lone king lands. The king and bishop do most of the work of forcing the king to the edge of the board. The knight is used to close off important flight squares.
My suggestion to my fellow improvers is to make slight changes to these positions and work them through to checkmate. That way, you’ll really understand what is going on and not memorize solutions.