Saturday, July 18, 2015

Reti's Tightrope Maneuver: Part 1

A chessboard consists of 64 squares. To the common man it might seem like amazingly boring terrain upon which to wage war. But to the chessplayer, knowledge of chessboard geometry-- especially with pieces involved-- can be an interesting element, and sometimes the factor that decides between a win or loss.

We have already touched on elements of the chessboard by talking about the long and short sides of the board in rook endgames. Today, we will look at another example of chess geometry in action: Reti's tightrope maneuver.

No, you don't need Ptolemy's Theorem or the cosine rule to work this out. Just a simple understanding of the diagonals and good king footwork will do. Take a look at the puzzle below, published by Richard Reti in 1921:

Reti, Richard
Kagans Neueste Schachnachrichten 1921
White to move and draw

At first glance, it seems that White's position is hopeless. His king is well out of the square of Black's pawn (see this Wiki article if you're not sure what that means) and has no way to catch it. On the other hand, Black's king is only two squares away from capturing White's pawn! So White should resign... or should he?

Take some time to look at the position, before scrolling down.
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Reti discovered that White could draw in this position, by exploiting the diagonal to go on a risky "tightrope" maneuver. Precision is needed here:

1. Kg7!

Black's king has to spend two tempi to capture the pawn, which is enough time for White to enter the square of the Black pawn. Thus, White can exploit the diagonal to get closer to both pawns at the same time.

1... h4

If 1... Kb6 2. Kf6 Kxc6 3. Kg5 White captures the pawn.

2. Kf6 Kb6

2... h3 and White just goes over to escort his pawn: 3. Ke7 h2 4. c7 Draw.

3. Ke5

The point of White's "tightrope" maneuver is to ether step into the square of Black's pawn, or escort his own pawn to promotion.

3... h3

Once again 3... Kxc6 allows White to get into the square of Black's pawn with 4. Kf4

It seems that Black's pawn cannot be stopped. Is it time for White to resign?

4. Kd6!

Of course not! White simply ignores Black's pawn and moves over to escort his own pawn.

4... h2
5. c7 Kb7
6. Kd7
1/2-1/2

And White's pawn cannot be stopped from promoting. Draw.


Amazing, isn't it? Reti's discover eventually became an important idea in king-pawn endgames, with the same motif being employed in many games and puzzle compositions.

Here I will leave 3 such puzzles for y'all as a challenge. Try using Reti's tightrope motif to solve them!

Position 1: White to move and draw

Position 2: Black to move and draw

Position 3: White to move and win

Once again, I will discuss the solutions next week. Have fun! (:

Sources:
"Silman's Complete Endgame Course" by Jeremy Silman
"Rosen's Chess Endgame Training" by Bernd Rosen
http://giphy.com/gifs/funny-fun-amazing-2U0vh8iE6ZYti

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