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Robin Smith

Joined: 08 Mar 2006
Posts: 2307
Location: Brownsville Texas USA

Post subject: Re: Is this positions drawn ??    Posted: Fri May 25, 2007 2:35 am

glorfindel wrote:
 Terry McCracken wrote: Robin, you improvised and even removed the Black h6 pawn and EGTBs returned a draw. What , more proof do Dan and Uri need??

I agree with Dann that this is the least convincing proof I have read in this thread. The proposal "remove the h6 pawn, and it is still a draw" is useless, because from the first moment Uri asked for proof that Black cannot be placed in zugzwang. It is well known that in such Q v R endings, two protected squares is all the Rook needs in order to defend successfully. If you remove the h6 pawn, you immediately give the black rook a second protected square for free.

I would like to add that I find Robin's proof to be convincing. But if the h6 pawn was missing, the position becomes simpler to evaluate as a draw and his proof would be shorter. He would not have had to prove that the black Rook will always have an available square other than f6. The proof would be something like "Rf6-h6-f6-h6-f6-h6".

Finally would like to bring in the opinion of a expert on this position, namely Mark Dvoretsky. In the book "Dvoretsky's Endgame Manual", Chapter "Queen vs. Rook", paragraph "A Fortress with Multiple Pawns", he analyzes the following position

V. Khenkin, 1962
[d]8/4K2k/4Q1p1/5r1p/7P/8/8/8 b - - 0 1

1... Kh8!? (1... Kg7 and 1... Rf1 are also good) 2. Qxg6 Rf7+ 3.Ke6 Re7+ with a draw by stalemate or perpetual check.

With a shift up, the position is still drawn. But when shifted down, it is lost: White wins by means of a queen attack along the last rank.

So Dvoretsky says our position is drawn, because if we shift Khenkin's position up, we get the structure of the game Topalov-Mamedyarov.

You make some good points. However there is also a certain irony in your claim about the h-pawn removal "proof" being unconvincing (even though I sympathize with that point of view). In the original position under discussion removal of Black's h-pawn did not affect the drawn outcome (it is not hard to see that the rook has plenty of squares anyway), while in this new position removal of Black's h-pawn results in a position that is no longer a draw. Part of Black's problem is that in the new position without the h-pawn Black actually has fewer tenable squares for his rook, not more, since the rook now needs to try to stay on the 6th rank, to prevent White's pawn push.
_________________
- Robin Smith
 Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First
Subject Author Date/Time
M ANSARI Fri May 18, 2007 8:15 pm
Tobias Lagemann Fri May 18, 2007 8:53 pm
Terry McCracken Fri May 18, 2007 9:01 pm
Uri Blass Fri May 18, 2007 9:17 pm
Robin Smith Fri May 18, 2007 9:35 pm
Alex Brown Fri May 18, 2007 9:47 pm
Uri Blass Fri May 18, 2007 10:29 pm
Torstein Wed May 23, 2007 12:33 pm
Paulo Soares Fri May 18, 2007 10:18 pm
nuff Fri May 18, 2007 10:27 pm
Paulo Soares Fri May 18, 2007 10:34 pm
Uri Blass Fri May 18, 2007 10:39 pm
Terry McCracken Fri May 18, 2007 10:53 pm
Dann Corbit Sat May 19, 2007 12:27 am
Terry McCracken Sat May 19, 2007 4:57 am
Dann Corbit Sat May 19, 2007 6:13 am
Terry McCracken Sat May 19, 2007 4:14 pm
George Tsavdaris Sat May 19, 2007 4:52 pm
Terry McCracken Sat May 19, 2007 6:15 pm
George Tsavdaris Sat May 19, 2007 6:20 pm
Terry McCracken Sat May 19, 2007 7:43 pm
Uri Blass Sat May 19, 2007 6:31 pm
Terry McCracken Sat May 19, 2007 7:39 pm
Alessandro Scotti Sat May 19, 2007 9:10 pm
Terry McCracken Sun May 20, 2007 3:27 am
Dann Corbit Wed May 23, 2007 4:17 am
M ANSARI Wed May 23, 2007 6:53 am
George Tsavdaris Wed May 23, 2007 4:19 pm
Dann Corbit Wed May 23, 2007 6:19 pm
Uri Blass Fri May 18, 2007 10:36 pm
nuff Fri May 18, 2007 10:41 pm
Uri Blass Fri May 18, 2007 11:50 pm
Graham Banks Fri May 18, 2007 11:59 pm
Uri Blass Sat May 19, 2007 12:03 am
Graham Banks Sat May 19, 2007 12:13 am
Robin Smith Sat May 19, 2007 4:00 am
Uri Blass Sat May 19, 2007 6:14 am
Terry McCracken Sat May 19, 2007 4:17 pm
Uri Blass Sat May 19, 2007 5:13 pm
Terry McCracken Sat May 19, 2007 6:09 pm
Dann Corbit Mon May 21, 2007 9:51 pm
Robin Smith Tue May 22, 2007 3:15 am
Dann Corbit Tue May 22, 2007 4:02 am
Terry McCracken Tue May 22, 2007 4:20 am
Robin Smith Tue May 22, 2007 10:24 pm
Terry McCracken Tue May 22, 2007 4:29 am
Dann Corbit Wed May 23, 2007 11:42 pm
J. Prata Thu May 24, 2007 12:19 am
Dann Corbit Thu May 24, 2007 12:42 am
Robin Smith Thu May 24, 2007 1:20 am
Terry McCracken Thu May 24, 2007 2:29 am
Robin Smith Thu May 24, 2007 3:21 am
Terry McCracken Thu May 24, 2007 4:29 am
Uri Blass Thu May 24, 2007 7:20 am
Terry McCracken Thu May 24, 2007 2:25 am
glorfindel Fri May 25, 2007 1:38 am
Terry McCracken Fri May 25, 2007 2:11 am
glorfindel Fri May 25, 2007 3:04 pm
Terry McCracken Fri May 25, 2007 5:04 pm
Re: Is this positions drawn ?? Robin Smith Fri May 25, 2007 2:35 am
glorfindel Fri May 25, 2007 3:25 pm
Richard Sutherland Fri May 25, 2007 3:50 pm
Terry McCracken Fri May 25, 2007 4:09 pm
Robin Smith Fri May 25, 2007 4:50 pm
Terry McCracken Fri May 25, 2007 5:05 pm
Dann Corbit Fri May 25, 2007 2:23 am
Terry McCracken Tue May 22, 2007 4:19 am
Dann Corbit Wed May 23, 2007 10:56 pm
Paulo Soares Fri May 18, 2007 10:15 pm
Uri Blass Fri May 18, 2007 10:26 pm
Paulo Soares Fri May 18, 2007 10:58 pm
Uri Blass Sat May 19, 2007 12:01 am
Paulo Soares Sat May 19, 2007 12:24 am
Daniel Mehrmann Wed May 23, 2007 11:40 pm

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