The Human Gnome Presents
Mating with Bishop and Knight

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      After watching a 190(BCF) with over an hour on the clock be forced to accept a draw after failing to force a mate, it occurred to me that in a match condition with only a few minutes on the clock the chances are I'd fail too.

      Luckily given a little study the situation becomes reasonably easy. The attacker needs only to remember a couple of basic positions:


Diagram 1: THE CAGE

      This is the position the attack aims to achieve. The enemy king is trapped on six squares unable to break free. Black wins by taking the d7 square with his King forcing the enemy king back further and the bishop manoeuvre Ba6-c8 followed By Kc7. Then mate is forced by Ne7-c6.

The general plan against accurate defense is:

      If the cage position is remembered, then forcing mate is very simple. The only step in the plan which is difficult against accurate defense is driving the opponents king from the wrong corner to the right one. The following three positions show how to do this:


Diagram 2: FORCING THE KING OUT

      Logically the corner square must be taken by the Knight, the next by the bishop. Black will make progress by Ne5-d7 attacking the next dark square (f8).

1. Ke8 Ne5
2. Kd8 Ke6

If white tries 2. Kf8 he actually delays mate by a couple of moves , but blacks moves are now very easy to find ...Nd7 black easily drives whites king to the correct corner.


Diagram 3: THE WHITE KING 'ESCAPES'

      It now becomes clear why under match conditions even Grandmasters have failed to force mate. Blacks pieces cannot keep the king on the back rank. In fact white can escape not only to the 7th rank, but to the 6th! The bishop appears to be a long way away doing nothing. It is here that the game often slips from blacks fingers.

3. Kc7 Nd7!!

      The ONLY move! In numerous games moves such as ...Kd5 have been tried in desperation and black loses the chance to mate (on this pass - its off to the wrong corner again).


Diagram 4: THE BEGINNING OF THE END

      Now white has only one try left for escape. Other moves can be met with sensible moves e.g. 4. Kd8 Kd6 or 4. Kb7 Bd3 (5. Kc6 Bc4 then 6. ...Bb5).

4. Kc6 Bd3

      And the door is firmly closed. Now black can easily set up the cage position and mate. The most obvious continuation if white tries to escape back to the wrong corner is as follows:
5. Kc7 Bb5!
6. Kd8 Nf6  
7. Kc7 Nd5+
       With check black creates the cage position shown above and forcing mate is simple.