Normal Topic R+3P vs. R+2P (Read 6651 times)
Smyslov_Fan
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Re: R+3P vs. R+2P
Reply #7 - 07/20/08 at 00:12:25
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I just found this thread.  I hope we can see a whole bunch of these sorts of questions here!  This is exactly the sort of challenge that I give my students (only a bit easier to solve) and that I need for myself!

(To surmise?  Micawber, it must still be summary for you too!)
  
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micawber
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Re: R+3P vs. R+2P
Reply #6 - 07/17/08 at 19:32:22
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Well, to surmise. Scarapawn got it right, and provided the winning variation. 
When I posted my 'intuition', I resorted more or less to general rules,
as I had no board available at the time. I actually calculated scarapawn's variation but mistakenly thought that black had even some drawing chances there, seeing that white at least couldnt count on a win he tried to keep his king in the neighborhood of the h-pawn (because of black's rank checks). But with the position on the board it is easy to see that white wins hiding his king on g7 or f7.
Thx scarapawn!
  
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Re: R+3P vs. R+2P
Reply #5 - 07/17/08 at 19:09:19
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Viking wrote on 07/17/08 at 18:43:03:
We are not computers. Can't always calulate till the end. Need some guidance to look for possible defencive ideas before converting it into pure variations.


Curiously, the computer wasn't much help: it gave White a big advantage, but then only recommended running endlessly from checks from Black's rook.  The game finished:

64.Rc8 Kb7 65.Rd8 Rg1 66.a6+ Ka7 67.Rd4 Ra1 68.Rg4 Rc1+ 69.Rc4 Re1 70.Kc6 Kb8 71.Rg4 Rc1+ 72.Kd5 Rd1+ 73.Kc5 Rc1+ 74.Rc4 Rf1 75.Rb4 Rf5+ 76.Kc6 Rf6+ 77.Kd5 Rf5+ 78.Ke6 Ka7 79.Kd7 Kb8 80.b6
1-0
  

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Re: R+3P vs. R+2P
Reply #4 - 07/17/08 at 18:43:03
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White is a pawn up, he has the most active king, c7 is weak. Using Marin's general rule white is at least two points up-white must be winning (which confirms my first impression).

I concluded with similar variations as already presented by sacapawn.

I have deep respect for micawbers endgame skills - so maybe I am wrong?

Of course we need general rules. We are not computers. Can't always calulate till the end. Need some guidance to look for possible defencive ideas before converting it into pure variations.
  
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Re: R+3P vs. R+2P
Reply #3 - 07/17/08 at 11:19:28
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I doubt that it is very meaningful to assess a position like this using general considerations. My experience from rook endings are that they often are decided by very specific details. So, a brief analysis suggests White is winning:

1.a6 (threatens Rc8) Rg1 2.Rc8 Rc1+ 3.Kd5 Rc2 (3...Kb6 4.Rb8+ Ka7 5.Rb7+ Ka8 6.Ke6 with similar play as the main line) 4.Ke6 Rc5 5.Kf6 Rxb5 6.Rxc7+ Kxa6 7.Kxg6 and White wins.
  
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Re: R+3P vs. R+2P
Reply #2 - 07/17/08 at 09:07:14
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This is intersting indeed, esp. the a-&h- pawns vs. no pawns for Black.

But I must admit I am confused with Micawber's point (b) above. I thought Black would have had more drawing chances if White actually plays b6 instead of a6. Then with White pawns on a5&b6 and a Black King on a6 it seems easier to hold the draw with an activated, checking Rook.

??
  

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micawber
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Re: R+3P vs. R+2P
Reply #1 - 07/17/08 at 06:04:41
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Hi,

I am interested in the way you won this endgame.
My first impression is like yours, that this position is probably drawn.
My considerations are more or less:
a) the endgame is drawn in most cases if the kingside pawns come off.
b) if the kingside pawns come and black loses his c-pawn, there are a number of drawn positions, provided white has played a6, and blacks king is not restricted to the back rank.
c) if black can exchange his g-pawn for whites b-pawn the game there are quite a lot of drawn positions.
So please show us the rest of the game!
  
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R+3P vs. R+2P
07/16/08 at 19:04:16
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I recently won an endgame as White in this position:

W: Kc5, Rh8, a5, b5, h4

B: Ka7, Rg4, c7, g6

White to play.


I guess it shows that I need to work on my endgames, but I had some real trouble with this, and thought that the position might actually be drawn before falling on the right continuation (which may--or may not--have been aided by my opponent).  I'd be happy to show the following moves, but is this game drawn, or do White's connected pawns (and pawns on either side of the board) ensure a White victory?
  

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