Wednesday, 27 June 2012

All you need to know about same colour bishop endgames

White to move
Today's football match between Spain and Portugal seems really boring in a first half and I thought that publishing a solution for bishop endgames can be as much interesting to do.
In position number one, a question was can white win this position.
An answer is negative, as white can not oppose black bishop from d7.
1. Bc8, Bg2
2. Bg4, Bb7
Now, white can try a same technique as with a b(g) pawn
3. Bf3 
...but that doesn´t help him, because black has enoguh
squares on shorter diagonal.
There is nothing White can do to win this position.
White to move
In this position, white king is placed better on b8 because he controls b7 square and he can oppose his bishop on b7.
So white can win this position.
1. Bc8, Bf1
2. Bg4, Ba6
Now, all that white needs is to transfer his bishop on b7.
3. Bf3, Kc5
Black´s idea is to play Kb6 but he is to late.
4. Bb7 
...and white promotes.
As we can see, black tried to transfer his king to b6 in order to save a game.
But, could that really save him?
White to move
Answer will give position number three.
1. Bc8, Bf1
2. Bg4, Ba6
White can not transfer his bishop to b7, because black firmly controls it.
But if he controls it, it doesn´t mean that he can step on it.
3. Bf3
...and a typical weapon in many endgames occurs.
An zugzwang.
White wins a game because black can not keep control of b7 square.
A fourth case was a bit more undefined.
We can imagine a position with a white king on d8 and a black king on b6. In that case white can win if he transfers his bishop on d7 before black can transfer his king to d6 (to control d7). If black manage to transfer his king, than we have a case number one, otherwise wins for white is trivial.
We can draw some conclusions about this type of endgames.

  • White wins in any case if his king is on b8 (or g8 if we look at the position from right).
  • White wins with a king on d8 if black king is not on d6
  • With a pawn on b (g) file white wins as I explaind in article Problem solving techniques
  • With a central pawn black draws easy, because shorter diagonal has a four squares, and only he needs to do is to keep his bishop from the opposite side from opponents king. Why? It is to easy and you can figure it out by yourself.
  • With a pawn on the edge (a or h file) white can win if he can place his bishop on long diagonal
The case with a(h) pawn is a bit special and I need to explain it on following example.
White to move
White plays as in previous examples:
1. Bg7, Bd2
2. Bh6, Bd4
3. Bg5
It seems that white will push his pawn to h7 and then play Bf6 but...
Black plays with a help of tactic.
4. Be7!
Again, black is in zugzwang and is going to lose.
This can not be taken as a general rule for positions with a(h) pawn. We can do a similar as in previous examples.
If we shift this position two ranks up, then we have a dead draw position because white can never push black bishop from long diagonal. He can not transfer his bishop on g7, because black is in control of this square, and he can not transfer his bishop on h8 because there is not shorter diagonal at all.
A sub-question was, what if black has king on e6 in position on diagram.
Of course, then we have a simple draw position because black can exchange bishops on h6 or g5 and reach a draw in pawn endgame.

As I understood in conversations with many players, endgames are not a favourite part of a game for many of them and many believes that one need to know much about it to play it well.
I believe that this endgame course is quite enough what you need to know about same colour bishop endgames up to IM level except a famous position with a tempo-winning method with a pawns on the same colour like a bishop (I will show that position in one of my next articles).

1 comment:

  1. Anders Johansson28 June 2012 at 12:08

    Your explanations are lucid and, in this reader's humble opinion, the examples chosen serve as an excellent introduction to endgames overall.