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Is this positions drawn ??
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Robin Smith



Joined: 08 Mar 2006
Posts: 2307
Location: Brownsville Texas USA
PostPost subject: Re: Is this positions drawn ??    Posted: Fri May 25, 2007 4:50 pm Reply to topic Reply with quote
glorfindel wrote:
smirobth wrote:

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.

The next position illustrates my point better, and it is the one I should have posted earlier. It is Topalov - Mamedyarov shifted one rank to the left.

V.Khenkin, 1966
[d]1Q6/5pk1/4r1p1/3K2P1/8/8/8/8 w - - 0 1
   WQ    ::    ::    ::
::    ::    :: BP BK    
   ::    :: BR :: BP ::
::    :: WK ::    WP    
   ::    ::    ::    ::
::    ::    ::    ::    
   ::    ::    ::    ::
::    ::    ::    ::    


Dvoretsky: As we know, a similar position, without the g6-pawn, is drawn. But here, when this pawn deprives the rook of the second protected square, White wins: he gradually approaches the black pawn using the zugzwang technique.

The main line he gives is 1. Qc7! (zugzwang) Re3 2. Qc2! Kg8 3. Kd6 Re6+ 4. Kd7 Re3 5. Qc4! (the Rook must leave the e-file) Ra3 6. Qe4 Kg7 7. Qe5+ Kg8 8. Qb8+ Kh7 9. Ke7 +-

Indeed this position is lost for Black. However I partially disagree with Dvoretsky's reason why. I believe the primary reason is that in this position Black's rook is no longer safe on e6! For example in the position given, if White's queen is on c8 instead of b8, then playing 1.Qxe6! immediately wins! After 1...fxe6 2.Kxe6 we have this tablebase win:
[d] 8/6k1/4K1p1/6P1/8/8/8/8 b - - 0 2
   ::    ::    ::    ::
::    ::    ::    BK    
   ::    :: WK :: BP ::
::    ::    ::    WP    
   ::    ::    ::    ::
::    ::    ::    ::    
   ::    ::    ::    ::
::    ::    ::    ::    

Tablebase win in 17

If Black had not had the g-pawn, then 1.Qxe6? fxe6 2.Kxe6 leads to an equivalent position where Black has one pawn less ... but now can draw the game!

[d] 8/6k1/4K3/6P1/8/8/8/8 b - - 0 2
   ::    ::    ::    ::
::    ::    ::    BK    
   ::    :: WK ::    ::
::    ::    ::    WP    
   ::    ::    ::    ::
::    ::    ::    ::    
   ::    ::    ::    ::
::    ::    ::    ::    

Tablebase draw

I should add that although in the 2 positions above I show it as Black to move, since White just played Kxe6, the results of neither position would change, even if it were White to move (thus it is not only when Black can capture White's pawn that the ending is drawn)

Thus it is largely the king and pawn ending where Black's extra pawn hurts his defense. In the original position where White's pawn is on the h-file, the king and pawn ending is always an easy draw since Black's king is nearby.

But never-the-less the main point of your post is still good.
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Subject Author Date/Time
Is this positions drawn ?? M ANSARI Fri May 18, 2007 8:15 pm
      Re: Is this positions drawn ?? Tobias Lagemann Fri May 18, 2007 8:53 pm
            Re: Is this positions drawn ?? Terry McCracken Fri May 18, 2007 9:01 pm
                  Re: Is this positions drawn ?? Uri Blass Fri May 18, 2007 9:17 pm
                        Re: Is this positions drawn ?? Robin Smith Fri May 18, 2007 9:35 pm
                              Re: Is this positions drawn ?? Alex Brown Fri May 18, 2007 9:47 pm
                                    Re: Is this positions drawn ?? Uri Blass Fri May 18, 2007 10:29 pm
                                          Re: Is this positions drawn ?? Torstein Wed May 23, 2007 12:33 pm
                              Re: Is this positions drawn ?? Paulo Soares Fri May 18, 2007 10:18 pm
                                    Re: ComputerChess is bad for you !! nuff Fri May 18, 2007 10:27 pm
                                          Re: ComputerChess is bad for you !! Paulo Soares Fri May 18, 2007 10:34 pm
                                          Re: ComputerChess is bad for you !! Uri Blass Fri May 18, 2007 10:39 pm
                                                Re: ComputerChess is bad for you !! Terry McCracken Fri May 18, 2007 10:53 pm
                                                      Re: ComputerChess is bad for you !! Dann Corbit Sat May 19, 2007 12:27 am
                                                            Re: ComputerChess is bad for you !! Terry McCracken Sat May 19, 2007 4:57 am
                                                                  Re: ComputerChess is bad for you !! Dann Corbit Sat May 19, 2007 6:13 am
                                                                        Re: ComputerChess is bad for you !! Terry McCracken Sat May 19, 2007 4:14 pm
                                                                        Re: ComputerChess is bad for you !! George Tsavdaris Sat May 19, 2007 4:52 pm
                                                                              Re: ComputerChess is bad for you !! Terry McCracken Sat May 19, 2007 6:15 pm
                                                                                    Re: ComputerChess is bad for you !! George Tsavdaris Sat May 19, 2007 6:20 pm
                                                                                          Re: ComputerChess is bad for you !! Terry McCracken Sat May 19, 2007 7:43 pm
                                                                                    Re: ComputerChess is bad for you !! Uri Blass Sat May 19, 2007 6:31 pm
                                                                                          Re: ComputerChess is bad for you !! Terry McCracken Sat May 19, 2007 7:39 pm
                                                                                          Re: ComputerChess is bad for you !! Alessandro Scotti Sat May 19, 2007 9:10 pm
                                                                                          Re: ComputerChess is bad for you !! Terry McCracken Sun May 20, 2007 3:27 am
                                                                                          Re: ComputerChess is bad for you !! Dann Corbit Wed May 23, 2007 4:17 am
                                                                                          Re: ComputerChess is bad for you !! M ANSARI Wed May 23, 2007 6:53 am
                                                                                          Re: ComputerChess is bad for you !! George Tsavdaris Wed May 23, 2007 4:19 pm
                                                                                          Re: ComputerChess is bad for you !! Dann Corbit Wed May 23, 2007 6:19 pm
                              Re: Is this positions drawn ?? Uri Blass Fri May 18, 2007 10:36 pm
                                    Re: Is this positions drawn ?? Save us all some trouble nuff Fri May 18, 2007 10:41 pm
                                          Re: Is this positions drawn ?? Save us all some trouble Uri Blass Fri May 18, 2007 11:50 pm
                                                Re: Is this positions drawn ?? Save us all some trouble Graham Banks Fri May 18, 2007 11:59 pm
                                                      Re: Is this positions drawn ?? Save us all some trouble Uri Blass Sat May 19, 2007 12:03 am
                                                            Re: Is this positions drawn ?? Save us all some trouble Graham Banks Sat May 19, 2007 12:13 am
                                    Re: Is this positions drawn ?? Robin Smith Sat May 19, 2007 4:00 am
                                          Re: Is this positions drawn ?? Uri Blass Sat May 19, 2007 6:14 am
                                                Re: Is this positions drawn ?? Terry McCracken Sat May 19, 2007 4:17 pm
                                                      Re: Is this positions drawn ?? Uri Blass Sat May 19, 2007 5:13 pm
                                                            Re: Is this positions drawn ?? Terry McCracken Sat May 19, 2007 6:09 pm
                                                                  Re: Is this positions drawn ?? Dann Corbit Mon May 21, 2007 9:51 pm
                                                                        Re: Is this positions drawn ?? Robin Smith Tue May 22, 2007 3:15 am
                                                                              Re: Is this positions drawn ?? Dann Corbit Tue May 22, 2007 4:02 am
                                                                                    Re: Is this positions drawn ?? Terry McCracken Tue May 22, 2007 4:20 am
                                                                                    Re: Is this positions drawn ?? Robin Smith Tue May 22, 2007 10:24 pm
                                                                              Re: Is this positions drawn ?? Terry McCracken Tue May 22, 2007 4:29 am
                                                                                    Re: Is this positions drawn ?? Dann Corbit Wed May 23, 2007 11:42 pm
                                                                                          Re: Is this positions drawn ?? J. Prata Thu May 24, 2007 12:19 am
                                                                                          Re: Is this positions drawn ?? Dann Corbit Thu May 24, 2007 12:42 am
                                                                                          Re: Is this positions drawn ?? Robin Smith Thu May 24, 2007 1:20 am
                                                                                          Re: Is this positions drawn ?? Terry McCracken Thu May 24, 2007 2:29 am
                                                                                          Re: Is this positions drawn ?? Robin Smith Thu May 24, 2007 3:21 am
                                                                                          Re: Is this positions drawn ?? Terry McCracken Thu May 24, 2007 4:29 am
                                                                                          Re: Is this positions drawn ?? Uri Blass Thu May 24, 2007 7:20 am
                                                                                          Re: Is this positions drawn ?? Terry McCracken Thu May 24, 2007 2:25 am
                                                                                          Re: Is this positions drawn ?? glorfindel Fri May 25, 2007 1:38 am
                                                                                          Re: Is this positions drawn ?? Terry McCracken Fri May 25, 2007 2:11 am
                                                                                          Re: Is this positions drawn ?? glorfindel Fri May 25, 2007 3:04 pm
                                                                                          Re: Is this positions drawn ?? Terry McCracken Fri May 25, 2007 5:04 pm
                                                                                          Re: Is this positions drawn ?? Robin Smith Fri May 25, 2007 2:35 am
                                                                                          Re: Is this positions drawn ?? glorfindel Fri May 25, 2007 3:25 pm
                                                                                          Re: Is this positions drawn ?? Richard Sutherland Fri May 25, 2007 3:50 pm
                                                                                          Re: Is this positions drawn ?? Terry McCracken Fri May 25, 2007 4:09 pm
                                                                                          Re: Is this positions drawn ?? Robin Smith Fri May 25, 2007 4:50 pm
                                                                                          Re: Is this positions drawn ?? Terry McCracken Fri May 25, 2007 5:05 pm
                                                                                          Re: Is this positions drawn ?? Dann Corbit Fri May 25, 2007 2:23 am
                                                                        Re: Is this positions drawn ?? Terry McCracken Tue May 22, 2007 4:19 am
                                                                              Re: Is this positions drawn ?? Dann Corbit Wed May 23, 2007 10:56 pm
                        Re: Is this positions drawn ?? Paulo Soares Fri May 18, 2007 10:15 pm
                              Re: Is this positions drawn ?? Uri Blass Fri May 18, 2007 10:26 pm
                                    Re: Is this positions drawn ?? Paulo Soares Fri May 18, 2007 10:58 pm
                                          Re: Is this positions drawn ?? Uri Blass Sat May 19, 2007 12:01 am
                                                Re: Is this positions drawn ?? Paulo Soares Sat May 19, 2007 12:24 am
      Homer can solve fortress draws Daniel Mehrmann Wed May 23, 2007 11:40 pm
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