Wednesday, April 16, 2014

Basic Endgame Essentials- King Pawn endings

Magnus Carlsen in Endgame training
White to move and draw, shown from black's side
Today we will have a look at some positions where in we will have to make a decision to after counting. But our aim today is to decide whether to transpose it into a simplified end game. So the basic question that arises is "How do we evaluate the endgame position?". So to answer this I'll talk about counting today.

Yes, King-pawn endgames/ King-Queen-Pawn endgames/ Rook-pawn endgames all require counting. This calculation will help us understand if the position is winning or drawish.

First I'll start with basic endgame counting. We'll also discuss about Opposition, triangulation techniques.

1. The basic King pawn ending.
Idea: To promote the pawn to the 8th rank and make it a Queen.
Technique: Keep the king in front of the passed pawn

Here both White and black have 'opposition'. This is a term used when the kings are in front of each other with  odd number of squares between them.
Why is opposition important ? Because the black king is restricted to move forward at any of the squares on 5th rank, and so is the white king.

The player to move in this position, will lose opposition.

The most important thing to note is "DO NOT LOSE OPPOSITION"

Case 1: White to play
If white moves the king to any square, he will lose opposition, and the game will end in a draw (How ?).
The diagram below shows the position which is the last thing you ever want as white (with black to play).
A stalemate
So white must play a pawn move, 1. e3. Now this forces the black king to move away. If black plays 1...Kf6 then 2. Kd5 else if black plays 1...Kd6 2. Kf5 and you want to reach this position below
Keep the promotion square protected.

Conclusion: White to play, white played 1. e3 to win, not losing opposition. This pawn move is called 'Tempo move' gains tempo on black king

PS: If instead of e-file the same structure was on a-file or h-file it will be a draw. Because Black will move to g-file (pawn on h2 case) and white does not have a file to move on the right.

Case 2: Black to play
Black is forced to move the king to either d6 / f6 or any on 7th rank.Thus the white king replies by going to  the opposite file and trying to protect the promotion square. Same as last diagram

2. Pawn boxes

A pawn on his home square requires 5 moves to reach the final rank. 1*(2 steps)+4*(1 step)
The King on g8 requires 5 moves to reach the b8 or b7 square to defend a8

Case 1: White to play
1. a5 wins!!

Case 2: Black to play
If the black king can get in the box marked by the green arrows in this move then he can save the game with a draw. But if he can't white will queen and win. 

3. Triangulation

Case 1: Black to play
Black must play to defend his pawn. And not leave it's defense. But that allows white to push his pawn further. 1... Kd5 2. f6 !! and white wins.

It gets tricky when white to play

Case 2: White to play
Candidate moves : 
1. Ke2
1. Kd2
1. Kc4 

Idea to block the black pawn's path. If the black king comes to 4th rank then push f pawn to promotion.
1. Ke2 Kf6 2. Kd3 Ke5 will go into 3 fold repetition
1. Kc4 Ke4 2. f6 d3 ... both will queen and will be almost equal until anyone blunders
1. Kd2 Kf6 2. Ke2 Ke5 3. Kd3 and now black to move, same position as above. Go to Case 1
This is what happened.

So key take away points
  • Losing opposition may result in loss
  • King must always be in front of passed pawn
  • It must always be important to understand who is to play and count the proper number of moves