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Later Kibitzing> |
| Sep-10-08 | | Marco65: <al wazir> <black has nothing better than 29...g6 30. Rd8+ Kg7 31. Bb2+ Kh6 32. Qh3#> In your (and Dr J's) line (24. bxc7 d5 25. Qc2 Rc8 26. Qc6 Rxc7 27. Qxe6+ Rff7 28. Rxd5 Rxc1+ 29. Bxc1) 29...h6 or 29...Qc7 might stop the threat and hold the piece, but of course White's advantage stays enormous. |
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| Sep-10-08 | | Alphastar: <MAJ> The most promising idea seems to be c6 followed by Bc5-d6 and c7 (or first c7 and then Bd6). Black will have to use his king and/or knight to stop the passed pawn from promoting. Meanwhile white brings his king up to c6. I cannot claim it is won for white, but this seems to be the best try. |
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| Sep-10-08 | | DarthStapler: I didn't get it |
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| Sep-10-08 | | BlackWaive: Strange Wednesday.
I searched for three or four minutes, and I couldn't find any candidate moves. According to Toga II 1.4β5c,
22. ♘b6 ♖af8 23. ♘xd7 ♖8f7 24. ♘b6 ♘xc5 25. ♘a4 ♕a6 26. ♕xa6 ♘xa6 27. ♖c6 ♘b8 28. ♖xe6 has an evaluation of +1.17 for White.
It seems that I should concentrate more on trying to win pawns... |
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| Sep-10-08 | | realbrob: <MostlyAverageJoe> Looking at your diagram above, if White can bring his king to b3, push the 'a' pawn and exchange it with Black's b pawn, his 2 passed pawns on b and c should be good enough to win. And at the moment I can't see a way for Black to prevent this. Also consider that Black's potential passed pawn are still far away from promotion and that White has a long-range piece, the bishop, which can easily guard the kingside, while Black has a knight. <About the puzzle> I also chose Nb6 because White had no other credible threats. |
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| Sep-10-08 | | zooter: <MAJ> My idea in your final position would be to play a4 and get connected b and c pawns..The bishop can stop the a-pawn as late as at a1 Though maybe an immediate a4 won't win |
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| Sep-10-08 | | eblunt: or alternatively :
22 ... ♗xb6 23 cxb6 ♕b5 IMO black is slightly worse. After praising yesterday's puzzle, I'm going to say this isn't one of CGs finest. against an optimum defence there's nothing clearcut that white has gained. |
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| Sep-10-08 | | hedgeh0g: Didn't get it :(
I thought the key move would result in trapping the Black queen... ...ah, but how wrong I was... |
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| Sep-10-08 | | TrueBlue: well, remember, this is 1) a puzzle b) you need to find only the next move. White has basically 2 puzzle moves:Rxd7 and Nb6. I spent 2 minutes, trying the first one, couldn't do it, so went for the second one. Here are the possible lines I found: 22. Nb6 Rd8 23. Qxa6 axb6 24. cxb6
and
22. Nb6 axb6 23. cxb6 Qe4 24. bxc7 Rc8
and black is even in more trouble here.
In the first line, no decisive advantage, but a nice way to get a passed pawn and break the game open.
About right for Wednesday.
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| Sep-10-08 | | nimzo knight: I can't figure out, why not 27..Nxc7 and 28..Kg8 (protecting h-pawn). Thanks in advance |
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| Sep-10-08 | | YetAnotherAmateur: <MostlyAverageJoe>From your position, I'd probably go with Kf2, and then work the queenside advantage like realbrob. Or alternately, use the threat of the passed pawn to break black's kingside position and release the e pawn. |
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| Sep-10-08 | | johnlspouge: Wednesday (Medium/Easy): Petrosian vs A Matanovic, 1959 (22.?) White to play and win.
Material: Even. The action is on the Q-side. White has Na4, Rc1, and Be3 supporting Pc5, which cramps the Black Q-side. In addition, the Black Qc6 is burdened with Na6 (attacked by Qe2), Pd7 (attacked by Rd1 on the semi-open d-file), and Ra8 (which is not yet attacked). If possible, a combination should be targeted at the overburdened Black Qc6. Candidates (22.): Nb6
22.Nb6 (threatening 23.Nxa8 and 23.Nxd7)
Black can feasibly accept the sacrifice in 2 ways:
(1) 22…axb6 23.cxb6 (threatening 24.Rxc6)
If the Q makes any feasible move other than 23…Qb7, Black drops material after 24.bxc7, which threatens both 25.c8=Q and 25.Rxd7 26.Rd8+ 27.cxd8=Q+. Thus, 23…Qb7 24.bxc7 (threatening 25.Rxd7 26.Rd8+ 27.cxd8=Q+) White has now won a P, so the variation is justified if the P can be held. Black is about to drop Pd7, however, and has only one feasible move to save it: 24…Qc8 25.Qf3 (threatening
26.Qxa8 Qxa8 27.c8=Q+ Qxc8 28.Rxc8+
winning a R for P)
25…Nxc7 26.Rxc7
White wins N for P because the Black Ra8 depends on the support of Qc8: 26…Qxc7 27.Qxa8+. (2) 22…Bxb6 23.cxb6 Qb7 [else, drop Na6] 24.bxa7
White has won a P, because the Black Qb7 burdened with Na6. Black can decline the sacrifice, but must move Ra8 to avoid dropping the exchange: (3) 22…Rd7 [else, drop Pd7 to 23.Nxd7]
23.Qxa6 axb6 [else, drop a N] 24.cxb6
and Black loses material.
The game followed my variation (1), but deviated at 24.Rxd7 instead of my 24.bxc7. According to Toga II 1.3.1, my variation also wins handily at more than +2.5 Ps, but the best play from the puzzle position was [ply 15/58 time 01:44 value +1.09]
22...Raf8 23.Nxd7 R8f7 24.g3 g6 25.g4 Rd5 26.Ne5 Bxe5 27.fxe5 Rf8 28.Rxd5 Qxd5 29.Bh6 Qf3 30.Qxf3 Rxf3 31.b4 Rxa3 32.b5 (Humans can improve near the end of the full computer variation.) |
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| Sep-10-08 | | Marmot PFL: The key in this position seems to be forcing black to open the c file, exposing his queen and bishop to the rook on c1, so Nb6! is the move. If black declines the win is easy-
22...Raf8 23.b4 and the threat b5 is decisive ex. 23...Bxf4 24.Bxf4 ab6 25.b5 Qa8 26.ba6 Rxf4 27.cb6 and the passed pawns decide. Accepting with 22...ab6 also loses, 23.cb6 24.Rxd7 and white recovers material, remaining with 2 passed queenside pawns. |
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| Sep-10-08 | | Marmot PFL: People that didn't find solution - remember, this is Tigran Petrosian, not Tal or Spassky, so don't just look for queen sac to mate or similar moves. Not that Tigran couldn't do that, but much more typical was petit combination simply leading to a better endgame. |
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| Sep-10-08 | | JG27Pyth: <True Blue: well, remember, this is 1) a puzzle b) you need to find only the next move.> Well, keep in mind that this is
A) a position from a game and 2) many of us think that the first move is often (even typically) not good enough -- one needs to get key moves deeper in, such as finding replies to critical defenses in order to receive (self-awarded) full credit. (III) Some days however I award myself full credit just for showing up. Finally, -- It really is a strangely non-forcing non-decisive problem, and it would seem Matanovic didn't strain himself looking for the best defense. I was surprised to see him accept the N. |
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Sep-10-08
 | | gawain: I was completely stumped. Medium/easy??? Well I am glad I was not the only one who found it more difficult than that. |
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| Sep-10-08 | | YouRang: Shoot. I even gave 22.Nb6 a passing glance, although I only had in mind the idea to block the defense of Na6 from my Q (which is sort of a lame idea anyway), but then 22...axb6 and the N is guarded after all, so I discarded the whole idea before considering 23.cxb6! :-( But then again, looking at the continuation, I doubt I would have calculated that right anyhoo. Tough Wednesday puzzle. |
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| Sep-10-08 | | johnlspouge: <<Marmot PFL> wrote: People that didn't find solution - remember, this is Tigran Petrosian [snip]> I try to view a puzzle position on its objective merits, but today I could not. Chessplayers (like mathematicians) have distinct styles, so once I saw the name "Petrosian", I started looking for the overburdened piece :) |
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| Sep-10-08 | | kevin86: I had no shot at this one. I briefly looked at Rxd6-but it seems to go nowhere. |
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| Sep-10-08 | | patzer2: For today's Wednesday puzzle solution, White combines the Knight Fork, discovered attack and pinning tactics for a strong advantage with the clever 22. Nb6!  .Apparently, Black can put up more resistance with the computer line given by <MostlyAverageJoe>. However, the game line is still instructive -- even for strong human play. |
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Sep-10-08
 | | chrisowen: Good heavens weird isnt it? With this one, should white also inspect 25. Qd2 Rxd7 Qxd7? Looks like 20. Be5? is aactually where black gott fried, on a points scale it rates sub zero. What now? we try spinning buckets? |
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| Sep-10-08 | | Marmot PFL: < johnlspouge> You are right, objective analysis is the way to go, but some of us need hints...Up to Wed/Thurs I can usually find best moves based on position, but from Fri on am often guessing. |
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| Sep-10-08 | | ruzon: Funny that I seem to have come in above average this time, finding the game line all the way to Rxd7, not that the game line is the best line for Black. |
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| Sep-10-08 | | whiteshark: Got the idea of advancing ♙c5 in combination with 22.Nb6 rather quick. Definitely a bit less subtle than the normal Thursday puzzle, which usually don't get. |
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Sep-10-08
 | | al wazir: After 22. Nb6 axb6 23. cxb6 Qb7 24. bxc7 d5 25. Qc2 Rc8 26. Qc6 Rxc7 27. Qxe6+ Rff7 28. Rxd5 Rxc1+ 29. Bxc1, I rejected 29...h6 because of 30. Rd8+ Kh7 31. f5, threatening 32. Qg6#. (If 31...Rf6, then 32. Qg8#.) I didn't consider 29...Qc7, which looks more promising. After 30. Be3 Nb8 31. Rc5, black has had the weenie, but if instead 30...Qe7, I don't see anything better than 31. f5, with a probably won endgame. |
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Kibitzing
sac: 22.Nb6