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| Jun-03-11 | | agb2002: White is a bishop up.
White wins by closing a mate net with 62.Rb1 Kh6 63.Rb7 Rh8 64.Kg4 Rg8+ (else 65.Rh7#) 65.Kh4 Rh8 (65... Rg7 66.Rb6+ wins the rook) 66.Ra7 zugzwang. |
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| Jun-03-11 | | zb2cr: Missed, missed, missed. I fell for the game line, not seeing 62. ... Rf6. |
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| Jun-03-11 | | sevenseaman: Sometimes a check comes at the very end, at other times there
seems no end to them. Its not a puzzle you solve in 'so many' moves.
Like in <CG>'s POTD, just get to a winning/material position as
soon as you can.
B. Horwitz, 1881.
click for larger viewWhite to move.
"Medium/Easy" |
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Jun-03-11
 | | Phony Benoni: I'm feeling better now. By the way, the Nalimov tablebase shows that the rook back/rook up/Kg4-h4 idea is the only way to win. White can get there via a different order of moves; for example, any safe rook move along the sixth rank doesn't spoil the win but merely delays it. |
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| Jun-03-11 | | sevenseaman: <Once>
The case <when you think you know and when you 'know' he knows.>There once was a white missionary in a village of all blacks. (not the NZ All Blacks). It so happened that the headman, after a progeny of 16 blacks to his pride got the 17th, all white. Eternal mortification and embarrassment, the matter needed to be sorted out without delay. So he accosted the missionary on a deserted jungle road. There was purpose on his mind, "And father, howcome?" Impelled by imminent danger to life and limb, the missionary implored he could explain, if the headman loosened the death grip on his throat a bit. Inspired by the peril and not a little by the evolutionary theory of atavism, the breathless priest pointed to a hill top. You see them sheep on the hill. Notice all but one are white. The black one is .... The death grip slackened of a sudden.
"Ok, ok! you no tell, I no tell". |
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| Jun-03-11 | | mqhelisi: I am very very happy to have got this one after only finding a secondary winning move on yesterday's. |
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| Jun-03-11 | | Patriot: Klaman was a pretty good player, wasn't he? Well at least I made the same move he made. ;-) I wonder if he missed the possibility of 62...Rf6 as well or just didn't have time to figure it out. |
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| Jun-03-11 | | David2009: K Klaman vs Kholmov, 1949 White 62? The challenge here is to find the win withouit looking it up in the table base. Black has chosen the sideways defence which
is less common than the normal defence (checking from the rear, in this case by Ra4) but which is trappy. White finds the win by a process of elimination.
First, 62.Rb7 (threatening Rh7#) immediately is bad because of 62...Rf6! and Black has the 'Szen draw'. This leaves 62.Rb1 (or Rb2 or Rb3, the same thing)
forcing 62...Kh6. Now 63 Rh1+ or Rg1 let the prey slip (if 63 Rg1 Rf6! draws) so 63 Rb7 Rh8 (forced) 64 Rf7! Kh5 (forced) 65 Rf6! Kh4
White has made progress but still has to be careful: e.g. 66 Bg4?? Rf6 draws by statemate. Instead 66 Rb7 Kh5 67 Bg4+ Kh4 68 Rb1 Rf8+ 69 Bf5 and this time there really is no escape.
Time to check. Kudos to everyone who solved this one OTB. A useful resource is www.chesstempo.com where you can practice up to two five-man endings a day for
free.
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Very interesting note presumably by <chessgames.com>: <??; White can force victory at once with 62.Rb3 (Rb2, Rb1) Kh6 63.Rb7! Rh8 64.Kg4! Rg8+ 65.Kh4 Rh8 66.Be4 zugzwang  >
Does my line win? time to check.
click for larger view Crafty End Game Trainer link:
http://www.chessvideos.tv/endgame-t... My line is not a disaster, but by itself cannot force the win since after 65.Rf6 Black can defend with 65...Rg8! instead of 65...Kh4. Now I have to retrace my steps with 66.Rf7 Rh8 and find 67.Ra7 Kh6 68.Kg4 Rg8+ 69.Kh4 Rh8 70.Rb7! zugzwant (effectively the same line as the note). I have to wait to play this out against the EGT (which has frozen at the time of posting: I can set the position up but not play it out), so I looked up the variations on my favourite tablebase: http://www.lokasoft.nl/tbweb.aspx Incidentally this now provides six-man endings: thanks Lokasoft! |
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| Jun-03-11 | | patzer2: In my attempt to solve today's Friday puzzle, I got as far as 62.Rb3 Kh6 63.Rb7 Rh8 64.Kg4 Rg8+, but I didn't see that 65. Kh4! initiated a mate-in-three with a clever zugzwang after 65...Rh8 66. Ra2 (or almost any Bishop or Rook move) 66...any Rook move (now forced) and 67. Rh7#. P.S.: <Jimfromprovidence> Thanks for the excellent post, diagrams and illustration. I learned something from them today. |
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| Jun-03-11 | | kevin86: I think that two question marks is CRUEL. It was a complicated combination to execute. AND,it only cost half a game. ?? should be saved for an obvious egregious blunder. Opinions? |
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| Jun-03-11 | | Once: <kevin86> Good point. Perhaps there ought to be a sliding scale for denoting blunders? We might need to make an adjustment depending on whether we are annotating a blunder that we made, or a blunder that our opponent made. Let's have a little doodle and see what we come up with. Here's one possible list for blunders that we make: ?? - a dreadful mistake, missed a mate in 1, threw away a win, left a piece en prise, foolishly accepted that cup of undrinkable tea, accidentally succumbed to a bout of flatulence and my opponent gave me a withering stare. Insert typical sufferingbruin comment here. ? - your plain common or garden mistake. Should have done better. Genuine self-shin-kick under the table. Slink away home quickly before the team captain asks me how I got on. ?! - an understandable mistake. Okay, so it loses, but it looked good, the other guy followed it up really well, the sun was in my eyes, I've had a hard day at the office, did she have to wear such a low-cut blouse? !? - a valiant try. A macho sacrifice which doesn't quite work, a brave bluff, a principled move, do I get any marks for style or artistic merit? And then there's the final category. In some instances, we don't put a ? against our own move, we put a ! against the opponent's reply. And when we do this we are saying "okay, so my moved lost, but he had to find a brilliant move to defeat it." And I think that today's POTD falls into that last category. And, yes, maybe I am saying that because I didn't spot it! ;-) Of course, we need to adjust our definitions if we are annotating our opponent's moves. In that case, we might come up with something like this: ?? - an unforced error. He didn't need to cave in so quickly against the might and magnificence of my brilliant attack. ? - my strategy pays off and forces him to play a poor move. It was inevitable really. ?! - I have no idea why he played that, but it doesn't look good. !? - I have no idea why he played that, but I wish I had thought of it. ! - why must I lose to this idiot?
!! - yes, well, of course, he has a higher grade than me. |
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| Jun-03-11 | | Patriot: <kevin86> I think it is subjective about what is an obvious mistake and what isn't. What we do know is that 62.Rb7 changed the outcome of the game, from a winning position to a drawn position. The mistake was not obvious to me since I also chose 62.Rb7. But perhaps any move that changes the outcome of the game deserves ??, whether it's an obvious mistake or not. It's a good question and something I've always wondered about. |
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| Jun-03-11 | | patzer2: correction: After 62.Rb3 Kh6 63.Rb7 Rh8 64.Kg4 Rg8+
click for larger view65. Kh4! is mate-in-seven after 65...Rg7 66. Rb6+ Rg6 67. Rxg6+ Kh7 68. Kg5 Kh8 69. Kf6 Kh7 70. Kf7 Kh8 71. Rg8#. It is mate-in-three after 65. Kh4! Rh8 66. Ra2 (or 66. Be4) 66...Rg8 (or any other Rook move) 67. Rh7#. |
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| Jun-03-11 | | tatarch: Good puzzle. I missed it.
<kevin86: ?? should be saved for an obvious egregious blunder. Opinions?> Agreed. |
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| Jun-03-11 | | estrick: <Phony Benoni: the Nalimov tablebase shows that the rook back/rook up/Kg4-h4 idea is the only way to win.> I've heard that this is a notoriously difficult ending for even masters to win. Wonder if I'll be able to store the winning idea and access it when and if I ever find myself in this situation? |
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| Jun-03-11 | | VincentL: <Difficult>I have tried various approaches but have not found the solution. The main work (driving the king to the edge of the board, etc) has been done, and perhaps it should not be difficult to finish the job, but after looking for some 10 minutes at this I cannot say I have made progress. There is no point in writing up my failed lines. Let´s see what happened. |
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| Jun-03-11 | | VincentL: Well, when you see the solution it looks easy. But it defeated the game participants and also most posters on here (perhaps surprisingly) so now I don´t feel quite such a duffer today. |
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| Jun-03-11 | | ruzon: I think the reason the solution is hard is because we know that to force checkmate, White's rook has to go either over the bishop and king or under them. So once you move up or down you figure your next rook move has to be to the right, but in this case you have to go down and then up. And then you have to see a tricky zugzwang but I didn't see that far. |
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| Jun-03-11 | | VincentL: I realised a zugzwang was probably the answer, but did not consider moving the king to the h file, and penning the black king in with R and B. If I had known to do this then maybe, just maybe, I would have solved it. |
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| Jun-03-11 | | MaczynskiPratten: Rb7 looks obvious because it is the most forcing. I found the Kg4 and Kh4 idea after a few minutes and was feeling pleased with myself until I read about Rf6. If you see a good move, look for a better one! Never mind, it's still a beautiful puzzle with its elegant economy of force. Another bullseye for cg.com. <Once>'s annotation interpretations gave me a good chuckle, as usual. His daily posts also ought to be annotated: ! smile
!! audible chuckle
!!! lol
Can't remember any ?'s or ??'s. |
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| Jun-03-11 | | MaczynskiPratten: Personally I'd go for the enhanced scale for (serious) annotations: ??? A gross blunder which loses instantly
?? A mistake which changes the course of the game in one move, even though it may have been difficult to
spot
? A clear mistake which worsens the position
?! A dubious move (e.g. which may be playable but doesn't work out well in the game) But I must admit that ?? feels very harsh for this one. Maybe I'd like to give it one-and-a-half ?'s. Or, like some commentators, give ? for missing a tricky win but ?? for a major tactical or strategic mistake. |
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| Jun-03-11 | | SamAtoms1980: <Once> IMHO it's fair to say that this position fell into the fourth category, that is, the unknown knowns. The combination looked rather familiar to me once I saw it, and I'd probably seen it before. But, of course, I forgot it. On the other hand, it's nice to know that I'm in very good company. |
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| Jun-03-11 | | wals: Nalimov endgame tablebase
62.
Rb1,b2,b3 win in 12
Ra6,c6,d6,e6 win in 13
Rg6 win in 14 |
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| Jun-03-11 | | wals: Analysis by Rybka 4 x64:
d 27 : 11 min :
1. (#11): 62.Rb2 Kh6 63.Rb7[] Rh8 64.Kg4 Rg8+ 65.Kh4[] Rg6 66.Rf7[] Rg4+ 67.Bxg4[] Kg6 68.Rf5 Kh7 69.Kg5 Kg7 70.Rf2 Kg8 71.Kg6 Kh8 72.Rf8#[] 2. (#11): 62.Rb3 Kh6 63.Rb7[] Rh8 64.Kg4 Rg8+ 65.Kh4[] Rg6 66.Rf7[] Rg4+ 67.Bxg4[] Kg6 68.Rf5 Kh7 69.Kg5 Kg7 70.Rf2 Kg8 71.Kg6 Kh8 72.Rf8#[] 3. (#11): 62.Rb1 Kh6 63.Rb7[] Rh8 64.Kg4 Rg8+ 65.Kh4[] Rg6 66.Rf7[] Rg4+ 67.Bxg4[] Kg6 68.Rf5 Kh7 69.Kg5 Kg7 70.Rf2 Kg8 71.Kg6 Kh8 72.Rf8#[] 4. (#12): 62.Rc6 Rf7 63.Re6 Rf8 64.Re2 Kh6 65.Re7[] Rh8 66.Kg4 Rg8+ 67.Kh4 Rg4+ 68.Bxg4[] Kg6 69.Re3 Kg7 70.Kg5 Kf7 71.Bh5+ Kg8 72.Kh6 Kf8 73.Re8#[] 5. (#12): 62.Rd6 Rf7 63.Re6 Rf8 64.Re2 Kh6 65.Re7[] Rh8 66.Kg4 Rg8+ 67.Kh4 Rg4+ 68.Bxg4[] Kg6 69.Re3 Kg7 70.Kg5 Kf7 71.Bh5+ Kg8 72.Kh6 Kf8 73.Re8#[] |
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| Jun-03-11 | | M.Hassan: "Difficult" White to play 62.?
White is a Bishop up.
62.Rb2 with the threat of mate on h2
62...........Kh6
63.Rb7 Rh8
64.Kg4 Rg8+
65.Kh4 Rg6
It is easy for Black to exchange the Rook with his Bishop and win the game by Rook+King vs King endgame,but, there is one problem and that is Black can only play with his Rook and the King can not move.So, next move Black has to move the Rook:
66.Rf7 Rg4+
67.Bxg4
Now, White can mate with stronger force. Time to check ---------
Way different |
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