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Tricky Win With Rook vs Bishop II 
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Pawn

Joined: Thu Sep 02, 2010 3:49 pm
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Rating Class: Novice (<1200)
Post Tricky Win With Rook vs Bishop II
Must be very tricky this endgame :roll:
I desperately tried to solve it - only a draw
I thought humbly Kasparov must have found the solution overthe board - but the master himself: draw
Next idea was to make a calculation with Rybka 4 - but: out of Rybkas deep throat came a draw too

:lol: far beyond my level of understanding


Sat Sep 04, 2010 1:03 pm
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Joined: Sat May 10, 2008 3:37 pm
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Post Re: Tricky Win With Rook vs Bishop II
Image

This is one of the more complicated endgames (and you probably won't get it in an actual game either because of the weird piece placement!).

But I'll give it a shot at explaining. First, before I go any further, check out this position:
Image

Take a moment and convince yourself that with black to move, white wins the black pawn on a4. The bishop has no squares where it defends the pawn. One important note, this works because black's king is stuck on the queenside. So if you are white, don't let black's king cross the d file!

Ok, so this is obviously the position that we're going to try to achieve when we have this endgame. How do we do it? Well, if you look at the position that we start with, white is fairly close to the zugzwang position. That said, the winning process is still ~15 moves.

Our first few moves are designed to keep black's king on the a8, b8, and c8 squares. White should play Re8-d8, and then Rd7+. When the black king moves to the 8th rank, white then brings his king to c6 to support the rook.

Image.

So the first stage is complete, black's king is stuck on the 8th rank on the queenside. Now the tricky part - obtaining the zugzwang position.

First, we have to force the black bishop to a bad square. The best way to do this is a maneuver like Rd7-d3-d4. You should get to a position like this:

Image

Your position might vary depending on how black plays, but the key feature is that white cannot take the pawn because of the skewer on e8.

So we play Kc5 and then try to take advantage of the bishop's poor position to force this position:
(Play Kc5, and then when the bishop goes to e8 to defend the pawn, play Re4 to attack the bishop)
Image

After you attack the bishop, it has to move to d7, allowing Re7, pinning it (assuming that black has played his king to the 7th rank). In this position, if it is white to move, play Rf7 and give the move to black. Black must play Kc8 or Kd8, and then white plays Kd6. If black played Kd8, congratulations, it's mate in 9 starting with Kd6. If black played Kc8, you have to work a little bit more. After Kd6, black will move the bishop. If the bishop goes to the kingside, you win routinely with Rc7+ followed by Kc6-b6. If black retreats to b5, then it's time to waste another move by playing Rh7 (or g7, f7, e7). After the bishop moves, give a rook check on c7 and then plays Kc6 and Kb6 to get to this position:

Image

Black has brought his bishop to d1 because other squares are much worse! If the bishop is on any other square, white will move the rook along the 7th to attack the bishop and threaten mate at the same time. That would end the game quickly!

But in any case, from this position, black must play Bb3 to defend the pawn and the bishop and now do you see how to get to the first zugzwang position?

Hidden Text Below - [Show it] - [Hide it Again]



Now that you've won the pawn, the rest is straightforward. It is easiest to win as white if you cut black's king off and force it to the kingside and then use your own king to bring up the pawn and win the bishop.

Good luck!
http://www.chessvideos.tv/endgame-train ... -ii-29.php


Thu Sep 16, 2010 1:38 pm
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Pawn

Joined: Wed Oct 20, 2010 8:39 pm
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Post Re: Tricky Win With Rook vs Bishop II
i already got the answer of the puzzle. . .


Wed Oct 20, 2010 8:42 pm
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Knight
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Joined: Wed Jun 11, 2008 12:54 am
Posts: 82
Location: Romania
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Rating Class: Class B (1600-1800)
Post Re: Tricky Win With Rook vs Bishop II
Nice explanation, thanks alot :)

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Thu Oct 21, 2010 1:25 am
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