LinearUnlock your Genius November 2008 (Problems)
Very nice position, Tony, many thanks for posting it!
I will dwell on it during the weekend, and post my thoughts. In the meanwhile, I am opening the thread, just in case someone wants to already comment.
Unlock your Genius November 2008
Well, it looks like White can't allow Rxe4+ if he wants to have any hope of winning, so Bxa4 is out. With that in mind, we can more or less ignore the relative strengths of the minor pieces, since White will be forced to play Bf5 in the next 1-2 moves, and Black will likewise be forced to reply Nxf5 to avoid checkmate.
The question seems to be whether to play Bf5+ immediately (intending Rf7 and Rxf6+ after the forced sequence Bxf5 Nxf5 exf5+ Kh6 Rf7), or play h5+ Kh6 Bf5 Nxf5 Kxf5, and instead use the king to penetrate when the time is right.
Bf5+ immediately is much more forcing, and both the f6 and d6 pawns will fall no matter what Black does, but he can get his rook behind his passed a-pawn (this is probably the "trick" Tony mentioned), ie:
1. Bxf5+ Nxf5 2. exf5+ Kh6 3. Rf7 a3 4. Rxf6+ Kg7 5. Rxd6, and now Black has Re4+ followed by Ra4. The position is still alive, as Black's king is under all sorts of pressure from white's king, rook, and multiple passed pawns all up in his face, but Black is two moves away from making a queen, if he is given the time to do it. I'll have to spend some more time looking at that position to see who wins first.
By the way, this is the reason for considering the h5+ and Kxf5 line; White's king keeps the black rook off e4 long enough to make sure the it's the white rook behind the a-pawn. It doesn't win 2 pawns right off the bat like the other line, but may be the safer alternative, and White should still be able to produce a lot of pressure once his king moves to e6, captures on d6, and starts to support the passed d-pawn.
Unlock your Genius November 2008
Unless I'm missing something here, I think both of the lines (Bf5+ Nxf5 exf5+ Kh6 Rf7 and h5+ Kh6 Bf5 Nxf5 Kxf5) lead to a forced win for white. Even in the positions where Black plays Re4+ - Ra4, his king just comes under too much pressure for him to make a queen in time:
1. Bf5+ Nxf5 2. exf5+ Kh6 3. Rf7 a3 4. Rxf6+ Kg7 5. Rxd6 Re4+ 6. Kg5 Ra4 7. f6+. There are various ways for Black to try to defend here, but all of them require his rook to move away from the a-file before he can queen, or he just gets checkmated. One example would be 7... Kf7 8. Rd7+ Ke8 9. Re7+ Kf8 10. d6 a2 11. d7 Ra8 12. d8=Q+ Rxd8 13. Ra7. Now white gets to scoop up black's a-pawn, his rook can easily get in front of black's remaining e-pawn, and it's a simple endgame to win.
Over the board, I would probably have chosen the other line, though. The Re4+ - Ra4 idea would have required way too much calculation for me at that point of the game (I had to spend a couple of hours looking at it just now, with the ability to move the pieces, etc), while the Kxf5 line is more simple, and still wins with an easy idea of "Get my rook behind black's a-pawn, take on d6 with my king, force Black to give up his rook for my d-pawn, and win with an extra rook." The rest of white's pawns just don't matter; Black can scoop them all up if he feels like wasting the time to do it, and White still gets an easy rook vs 2 pawns endgame.
Unlock your Genius November 2008
by Tony Kosten 
, France, Monday, November 10, 2008, 02:04 (6002 days ago) @ dlwyatt
Good so far! 
Unlock your Genius November 2008
I am afraid I have nothing to add, and my contribution will have to be limited to having opened the thread. :( I will have to wait for dlwyatt to be on vacation, if I want to say something! 
Unlock your Genius November 2008
? I am afraid I have nothing to add, and my contribution will have to be
? limited to having opened the thread. :( I will have to wait for dlwyatt to
? be on vacation, if I want to say something!
Sorry bout that : These couple of puzzles since we joined the site have been fairly uncomplicated endgames, so I tend to try to analyze them pretty thorougly. The older middlegame puzzles I looked at had a great number of ideas to choose from, and they seemed to have a lot more forum discussion going on. :)
Unlock your Genius November 2008
Just to prolong the discussion a little I wonder if an assessment of the position without deeper calculation could have reached the same conclusion.
At the start although B has a passed pawn it is not difficult to see that the
BKing is in trouble ,if the WKing could become more active , a very important factor in the ending , the attack against the BKing could become unstoppable.The forced variation that comes from Bf5 also makes that point more evident. Since the main factor in judging a chess position is the safety of the King ,that includes the ending,focusing on that idea could have been maybe enough to visualize a plan to achieve it. Of course keeping an eye on the passed black pawn.
Unlock your Genius November 2008
I sort of both agree and disagree with you here... a glance at the position is what led me to think that Bf5 was forced for White to have an advantage, and king activity was the #1 reason for that. Playing Bf5 forces the Black king to h6, allowing Rxe4+ would instead force my king to h3, so I immediately just started analyzing the two possibilities involving Bf5, and discarded Bxa4 without even looking at it too much.
After that decision was made, though, I had to go straight to hard analysis, first just running the "pawn race" without any particular finesses for tempo to see who won, then looking for every trick I could think of to sneak out extra advantage one way or the other. In the endgame, good ideas without concrete calculation are frequently doomed to lose you at least a half point. :)
It's such a pain to do that over the board. I've read "Think Like a Grandmaster" (which may be just about the greatest chess book I've ever owned), but still don't really have the knack for organized analysis on a timer. I still need to move the pieces and take notes to not overlook very important moves in positions like this.
Unlock your Genius November 2008
by Tony Kosten , France, Tuesday, November 18, 2008, 12:48 (5993 days ago) @ dlwyatt
? It's such a pain to do that over the board. I've read "Think Like a
? Grandmaster" (which may be just about the greatest chess book I've ever
? owned), but still don't really have the knack for organized analysis on a
? timer.
I read a scientific paper that said that humans were unable to analyse the way Kotov described in his book! All this business of trees and branches is nonsense!
Unlock your Genius November 2008
? I read a scientific paper that said that humans were unable to analyse the
? way Kotov described in his book! All this business of trees and branches is
? nonsense!
Well, I certainly hope there's something better than the way I play in competitive games. :) I just sort of intuitively see as many candidate moves and potential tactics as I can, right from the start, and just start playing through lines in my head. If I find something with a concrete advantage, most of the time, I just play it right away, without spending more time on that move. I am just as happy to cleanly win a minor piece as I am to win a queen, since it'll get me to the same place in the end almost every time.
The downside? I don't "see" everything, and sometimes overlook some doozies. Usually it happens when I'm so focused on my own tactics and attack, that I end up letting the other guy nail me with a perpetual check or worse. Tricky endgames like to bite me in the rear, too, if I miss a tempo-gaining trick for one side or the other.
The more structured analysis that I do with a pen and paper with lots of time (like for these puzzles) avoids those blunders, but I haven't figured out how to duplicate that in a real game.
Unlock your Genius November 2008
? I read a scientific paper that said that humans were unable to analyse the
? way Kotov described in his book! All this business of trees and branches is
? nonsense!
What paper would that be? I've seen a number of critiques of Kotov in chess literature, beginning, I think, with Tisdall's book, but don't know of any actual research in this area....
Unlock your Genius November 2008
by Tony Kosten , France, Tuesday, December 09, 2008, 12:43 (5972 days ago) @ sbd
? What paper would that be? I've seen a number of critiques of Kotov in
? chess literature, beginning, I think, with Tisdall's book, but don't know
? of any actual research in this area....
Try http://people.brunel.ac.uk/~hsstffg/preprints/Training_in_chess.PDF 
Unlock your Genius November 2008
Andrea - my workaround this has been to post before reading the other posts. It doesn't really matter how far out I am but at least I get to do some independent thinking. It's theoretically possible that I might post something sensible from time to time.
? I am afraid I have nothing to add, and my contribution will have to be
? limited to having opened the thread. :( I will have to wait for dlwyatt to
? be on vacation, if I want to say something!
Unlock your Genius November 2008
by Tony Kosten , France, Saturday, November 15, 2008, 12:12 (5997 days ago) @ dlwyatt
Can anyone see what would happen if Black queened on move 11 in this variation (preferably without moving the pieces, or using a computer!) Strange that no-one noticed.
Unlock your Genius November 2008
? Can anyone see what would happen if Black queened on move 11 in this
? variation (preferably without moving the pieces, or using a computer!)
? Strange that no-one noticed.
You mean instead of Ra8? I sort of thought the mate in one spoke for itself. :)
Unlock your Genius November 2008
by Tony Kosten , France, Monday, November 17, 2008, 12:58 (5994 days ago) @ dlwyatt
? You mean instead of Ra8? I sort of thought the mate in one spoke for
? itself. :)
Oops! My mistake, I assumed Black played the critical 8...Kf8 in this line. 
Unlock your Genius November 2008
? ? You mean instead of Ra8? I sort of thought the mate in one spoke for
? ? itself. :)
? Oops! My mistake, I assumed Black played the critical 8...Kf8 in this
? line.
I think you're asking about lines where White didn't get a chance to play Re7 with check (getting out of the way of the d-pawn with tempo). And you're right, of course, the line I gave was sort of the "easy one", where Black attacked White's rook whenever he could, but also walked into checks that White would have wanted to give anyway.
I'll shut up and let someone else take a crack at those. :)
Unlock your Genius November 2008
I'm kinda bummed that no one else has responded yet... I felt like I was hogging the action on this puzzle and didn't post for a couple weeks, and poof, the thread is dead.
Unlock your Genius November 2008
by Tony Kosten , France, Tuesday, December 09, 2008, 12:34 (5972 days ago) @ dlwyatt
? I'm kinda bummed that no one else has responded yet... I felt like I was
? hogging the action on this puzzle and didn't post for a couple weeks, and
? poof, the thread is dead.
Maybe I should put the answer online?
Unlock your Genius November 2008
? ? I'm kinda bummed that no one else has responded yet... I felt like I was
? ? hogging the action on this puzzle and didn't post for a couple weeks,
? and
? ? poof, the thread is dead.
? Maybe I should put the answer online?
I'm all for it, unless you have any more brain teaser questions to ask about this particular problem. :)
Unlock your Genius November 2008
Kg6! :) I'm pretty sure I didn't see that shot when I was analyzing the position (though I don't have the notes I took on it anymore). I remember having to go through all of Black's possible checks after Ke6 d8=Q to make sure he didn't have any tricks to take the pressure off his king without losing decisive material, which was why I preferred the Kxf5 lines as an "over the board" solution. I'm also pretty sure I didn't see the idea you gave of playing Black's rook to the f-file and making another passed pawn with f5.
Guess that's why you're a GM, and I'm a 1900 ish amateur. =)
Unlock your Genius November 2008
by Tony Kosten , France, Sunday, December 14, 2008, 14:04 (5967 days ago) @ dlwyatt
? Guess that's why you're a GM, and I'm a 1900 ish amateur. =)
Even I was feeling quite proud of myself when I saw the Kg6 nuance!
