Lessons on elementary pawn endings are frequently repeated in my teaching. Some students need multiple such sessions before they start using their king correctly. These lessons are also a regular part of my annual summer camp.
This week, the lesson will focus on a position that I created and then played against the computer while drinking my morning coffee. Several previous posts offer positions that I might use as well, if time and necessity dictate. See "Pawn Endings: The Key Position", "Rule of the Square", and "Six Pawn Endings".
White to move
Stripes,J -- Stockfish
iPad, 07.03.2017
1.Ke4
1.Ke3 is the only other winning move, but it wins in more moves.
1...Kd6
White to move
2.Kd4
The only winning move. It is in positions like this one that some young students want to push the pawn. The crafty ones try pushing the pawn only one square. A pawn move in this position will always draw if Black understands the basic drawing plan:
1) keep the king in front of the pawn as near as possible
2) step in front of the king to seize the opposition if it is not possible to move one or two squares in front of the pawn.
Hence,
a) 2.d3 Ke6 3.Kd4 Kd6 =
b) 2.d4 Ke6 3.d5+ Kd6 =
2...Kc6 3.Ke5
White executes an outflanking maneuver.
Here again, moving the pawn leads to a position that Black easily holds to a draw.
3.d3 Kd6 =
3...Kd7
White to move
4.Kd5
4.d3 is also possible. With White's king two squares in advance of the pawn, it is permissible to move the pawn one square. Play might continue 4...Ke7 5.Ke5 Ke7 Black grabs the opposition, but 6.d4 leaves the kings in their standoff, but transfers the move to Black. White thus seizes the opposition and will perform another outflanking maneuver on the next move.
Throughout this exercise, only one of my moves was not the best possible in the position. However, in many of the positions, there were one or more other moves that were equally good. In this case 4.d3 leads to checkmate in the same number of moves as 4.Kd5.
4...Kc7 5.Ke6 Kc6
White to move
6.d4
Now, moving the pawn is best. Two other moves also keep the win in hand, but checkmate in three moves further away. 6.d3 and 6.Ke5. Every other possibility leads to a draw.
6...Kc7 7.d5 Kd8
White to move
8.Kd6
This was the second time when White had only one move that secures the win. Stepping in front of a pawn that must advance may seem counter-intuitive, but it is precisely how the stronger side assures that the pawn will advance all the way to the queening square.
It is essential to alternate seizing the opposition and then giving it up until the king is able to control the promotion square.
8... Ke8
White to move
The three squares highlighted in red are called "key squares" because occupation of any one of them by White's king assures that the promotion square will be controlled.
9.Kc7
The White king occupies a key square.
9...Ke7 10.d6+
Black to move
Only now, with White's king contesting the rest of the pawn's march, is is possible to let the pawn move beside and then in front of the king without throwing away the win.
10...Ke6 11.d7 Kd5 12.d8Q+ Ke4
White to move
With a queen and king, White can now force checkmate in eight moves. It took me nine because of one small error. The process of learning how to checkmate with queen and king against a lone king often follows lessons on elementary pawn endings (see "Teaching Elementary Checkmates").
13.Qd2 Ke5 14.Qd3 Ke6 15.Qb5 Kf7 16.Kd7 Kf6
White to move
17.Qa5
17.Qh5 is faster.
17...Kg6 18.Ke7 Kh7 19.Kf7 Kh6 20.Qd5 Kh7 21.Qh1# 1–0
If I am not mistaken this is also called the principle of the keysquares.
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