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Mar-03-10
 | | chrisowen: Polished type of composition, Zoltan could allez the queenside passer. Does a6 pawn think I am a deus ex machina? Wolgang cranes his neck with 33..Rc7 yet the key b5 - b6 is the trap door. He belies his experience with 27..Rc4 when 27..Qb2 threatening Qxb4 looks more ave verum corpus. In a lot of this plot it is the a7/d7 devices that score it for him. |
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| Mar-03-10 | | turbo231: I meant to say the rook at c7 has to take the pawn at d7 or the pawn at (d7) will queen and black can do nothing about it. I played Rybka i thought rybka would move to the king to f8 but she dropped a pawn. It didn't matter the game ended up the same way. White had a rook and bishop, black had 4 pawns. Of coarse the first move is b6. |
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Mar-03-10
 | | Jimfromprovidence: <Random Visitor> indicated that 27 b6 wins. That move looks good, it's a more complicated version of today's puzzle. On that same note it appears white erred with 27 d5?!, allowing 27...Qb2, (threatening the white bishop), which black did not pick up on.
click for larger viewThe question is can white sacrifice the bishop and still play 28 b6? |
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Mar-03-10
 | | Once: Sometimes you've got to feel a little sorry for the humble prawn. As most chess tactics involve a double attack, the poor lumbering foot soldier just can't compete. A prawn can't pin, can't skewer and can only just about fork ... and then only if the opponents stand in exactly the right spot... But like the Zulus at Rourke's Drift, prawns do have one advantage over the better armed aristocrats of the chess boards - numbers. What prawns lack in firepower, they can sometimes make up for by bringing along a friend or two. Today's puzzle relies on two fairly standard pawn promotion tricks. Here's the first one: 
click for larger viewThe black a7 pawn seems to hold back both white pawns, but this is just an illusion. With 1. b6, white creates a double threat - he will either crown the b pawn (if black does nothing) or 1...ab 2. a7 and the a pawn queens. The second trick is this one:
click for larger viewAgain, the black rook seems to have it all under control but is quickly overwhelmed by pawn numbers. 1. a8=Q Rxa8 2. d8=Q. One pawn could be held back, but two are deadly. Combining these two motifs, and chucking in the extra bishop and rook, and we get today's pleasing little puzzle where the pawn Zulus overrun the British soldiders led by Stanley Baxter and Michael Caine. BTW, one of my favourite promotion tricks is this one: 
click for larger viewBlack cannot prevent white from queening one of the pawns. Even if we give black two consecutive moves, he still cannot prevent a pawn from queening. So perhaps the humble prawn is not so humble after all. And let's not forget that the Zulus may have been unable to win at Rourkes Drift, but they were rather more successful at the battle of Isandlwana just a few hours before... |
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| Mar-03-10 | | hedgeh0g: The fact that the position was so simple made this puzzle even easier than usual. A simple glance at White's advanced queenside, coupled with Black's tied-up rooks and weak back rank leaves b6! as the breakthrough move. |
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| Mar-03-10 | | Marmot PFL: 34 b6 was about the only serious candidate, combining promotion themes with back row mate threats. |
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| Mar-03-10 | | wals: GEORGE BERNARD SHAW
" Chess is a foolish expedient for making idle people believe they are doing something very clever when they are only wasting their time". and there is more on :-
http://www.notable-quotes.com/s/sha... |
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| Mar-03-10 | | jsheedy: ...b6! |
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| Mar-03-10 | | David2009: Wednesday 03/03/2010 puzzle Ribli vs Unzicker, 1985 White 34? 34 b6! promotes a Pawn. Some variations:
(A)...R(either)xd7 35 Rxd7 Rxd7 36 bxa7 1-0
(B)...Rxb7 35 axb7 etc
(C)...axb6 35 a7 etc
Time to check:
=====
Everyone has said it all. |
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| Mar-03-10 | | randomsac: b6 lets another pawn through. |
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| Mar-03-10 | | sfm: <wals: GEORGE BERNARD SHAW
" Chess is a foolish expedient for making idle people believe they are doing something very clever when they are only wasting their time".>
I have known this quote for 35 years. He's so right! LOL! |
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| Mar-03-10 | | TheBish: Ribli vs Unzicker, 1985 White to play (34.?) "Medium/Easy"
Thanks to the weakness of Black's back rank, White wins with a pawn breakthrough. 34. b6! axb6
Or 34...Rcxd7 35. Rxd7 Rxd7 36. bxa7 and queens next. 35. a7! Rxb7 36. a8=Q and Black can resign, since White mates after 36...Rxa8 37. d8=Q+ Rxd8 38. Rxd8#. |
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| Mar-03-10 | | reti: Fisher was right: "Always watch for a back rank checkmate." |
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Jul-04-20
 | | al wazir: Both 27...Bd6, preventing 28. Be7, and 27...g6/h6, creating an airhole and threatening 28...Rxb7, look better to me than 27...Rc4. For example, 27...h6 28. Be7 Qe5 29. Qxe5 Bxe5 30. a6 Rc4 31. d6 Rd4
32. Rxd4 Bxd4 33. d7 Bb6 34. Bd6 Rd8 35. Bc6 f6 36. Be7 Rb8. How does white make progress? |
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Jul-04-20
 | | drollere: (24) white can't take advantage of black's back rank weakness on the c file because d8 is twice protected. so R(a/d)c1 fails to protect the Q. 24. Qe3 loses the exchange, but 25. axb6 seems better to me. that's as far as i got. |
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Jul-04-20
 | | agb2002: White is a pawn up.
Black threatens Rxd2 and Bxd1 and exerts pressure on f2. White has Qe3, Qe1 and Qf4.
In the case of 24.Qf4 Qxf4 25.gxf4 Bxd1 26.axb6 Rc1 27.Rxc1 Rxc1 looks bad for White. Even worse is 24.Qe1 Bxd4.
After 24.Qe3 Bxd1 25.axb6 White threatens Rxd1 and bxa7: A) 25... Bg4(h5) 26.bxa7 Ra8 27.Bxb7 looks winning. B) 25... Qxb6 26.Rxd1 Qxb5 27.Bd2 unclear [2B vs r+p]. C) 25... Re2 26.Qf4 (26.Qf3 Re1+)
C.1) 26... Bb3 27.Qxf6 gxf6 28.bxa7 Ra8 29.Bxb7 as above. C.2) 26... Qxb6 27.Rxd1 and if 27... Qxb5 28.Bf1 wins decisive material. |
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| Jul-04-20 | | mel gibson: I wasn't sure.
Stockfish 11 agrees with the text.
24. Qe3
(24. Qe3 (♕d2-e3 ♗g4xd1
♖a1xd1 ♗b6-c7 ♗g2xb7 ♖c8-d8 ♗b4-e7 ♕f6-e6 ♗e7xd8 ♗c7xd8 ♖d1-a1 ♕e6xe3 f2xe3
♗d8-c7 b5-b6 ♗c7-b8 ♗b7-e4 ♖c2-c3 a5-a6 g7-g6 ♔g1-f2 ♖c3-b3 b6-b7 ♖b3-c3
♗e4-d5 ♖c3-c2+ ♔f2-f3 ♔g8-g7 e3-e4 ♖c2-c7 ♖a1-f1 ♖c7-d7 ♔f3-e3 f7-f6 ♗d5-c4
h7-h5 ♖f1-c1 ♖d7-e7 ♔e3-d3 ♖e7-c7 ♖c1-f1 ♖c7-d7 ♗c4-b3 ♖d7-c7 ♗b3-d5 ♖c7-d7
♖f1-c1 ♖d7-c7 ♗d5-c4 ♖c7-e7 ♗c4-b5 ♖e7-c7 ♖c1-f1 ♖c7-e7) +5.28/41 249) score for White +5.28 depth 41. |
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| Jul-04-20 | | Brenin: I kept trying to make the flashy axb6 work. It certainly doesn't on move 24 (24 ... Rxd2 25 Rxd2 Qxb6), and after <al wazir>'s line (B) 24 Qe3 Bxd1 25 axb6 Qxb6 26 Rxd1 Qxb5 White has 2B v R+P, with two connected passed pawns contend with, and the DSB looking for a safe square (eventually e3, to protect the potentially weak f2?); this position was far from clear to me, so 25 Rxd1, as played, looks best. |
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| Jul-04-20 | | RandomVisitor: A deeper look, following up on <mel Gibson>'s computer run:
click for larger viewStockfish_20070321_x64_modern:
<60/100 6:57:57 +6.45 24.Qe3 Bxd1 25.Rxd1> Bc7 26.Bxb7 Rb8 27.b6 Bxb6 28.axb6 Qxb6 29.Be4 Rcc8 30.Bc5 Qa6 31.Kg2 Re8 32.Qf3 Rbd8 33.Bd5 Qg6 34.Ra1 Qf6 35.Rxa7 Qxf3+ 36.Bxf3 h6 37.Bh5 g6 38.Bf3 Re6 39.d5 Re5 40.Bd4 Ree8 41.Bc3 Rd6 42.Bb4 Red8 43.Bxd6 Rxd6 60/97 6:57:57 -2.03 24.axb6 Rxd2 25.Rxd2 Qxb6 26.h3 Qxb5 27.Rb2 Be6 28.Rxa7 b6 29.Ra1 h5 30.h4 Qc4 31.Rab1 Qxd4 32.Bd2 Bf5 33.Be3 Qc3 34.Rxb6 Bxb1 35.Rxb1 Qc2 36.Rb5 Qd1+ 37.Kh2 Rd8 38.Re5 Qe2 39.Re7 g6 40.Bh3 Qd1 41.Bg2 Qd6 42.Rb7 Qe5 43.Bh3 Re8 60/104 6:57:57 -4.04 24.Qf4 Qxf4 25.gxf4 Bxd1 26.axb6 Rc1 27.Rxc1 Rxc1 28.Ba3 Ra1 29.Bb2 Ra2 30.bxa7 Rxa7 31.d5 Be2 32.b6 Ra6 33.d6 Rxb6 34.d7 Rd6 35.Bxb7 Rxd7 36.Be4 Ba6 37.Bc6 Rd2 38.Be5 f6 39.Bc7 Bc4 40.h4 Bd5 41.Bd7 Rd4 42.Kh2 g6 43.Kg3 Rd3+ |
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Jul-04-20
 | | Predrag3141: Over the board, almost all of us would get our queen out of hock with even material and a huge positional advantage. But it was presented as a Very Difficult problem so I only looked for a Very Difficult solution. This, like many puzzles of the day was more of a "What's the Best Move?" |
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Jul-04-20
| | Jimfromprovidence: I posted the below comment on March 3, 2010 concerning this game and I believe it is still relevant today. <... it appears white erred with 27 d5?!, allowing 27...Qb2, (threatening the white bishop), which black did not pick up on.
click for larger view
The question is can white sacrifice the bishop and still play 28 b6?> I also have this addendum...or find another move that keeps him ahead? |
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| Jul-04-20 | | NBZ: This is a strange puzzle, no? The most obvious sequence of moves (Qe3 Bxd1 Rxd1) looks strong for White. It is what White played in the game, and is also what 95% of players would play in this position in a normal game. |
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| Jul-04-20 | | RandomVisitor: Here is analysis using Lc0, a RandomVisitor first. This annoying engine keeps the entire search tree in memory, which continuously expands until it uses up all you have, at which point the program crashes. It is getting ready to crash, so this is the final post. Lc0 is using my graphics card to perform calculations.
click for larger viewLc0:
<23/59 4:32:26 132,904k 8k +2.34 24.Qe3 Bxd1 25.Rxd1> Bc7 26.Bxb7 Rb8 27.b6 axb6 28.a6 Ra2 29.Rc1 Bd6 30.Rc6 Ra1+ 31.Kg2 Qf5 32.Bxd6 Qd5+ 33.Qf3 Qb5 34.g4 Qf1+ 35.Kg3 Rd8 36.Rc7 f6 37.Bf4 h5 38.gxh5 Qb5 39.h3 Rxd4 40.Rc8+ Kh7 41.Be4+ f5 23/59 4:32:26 132,904k 8k -0.76 24.axb6 Rxd2 25.Rxd2 Qxb6 26.Bf1 h5 27.d5 Qf6 28.Re1 h4 29.Be7 Qc3 30.Bg5 f6 31.Be3 Re8 32.d6 h3 33.d7 Rd8 34.Bd4 Qxd2 35.Re8+ Kh7 36.Rxd8 Qxd4 37.Rh8+ Kxh8 38.d8Q+ Qxd8 23/59 4:32:26 132,904k 8k -2.72 24.Qe1 Bxd4 25.Rxd4 Qxd4 26.Bxb7 Rb8 27.b6 Re2 28.Qf1 Rxb7 29.Rd1 Qf6 30.f3 Re8 31.Qb5 Rbb8 32.fxg4 axb6 33.a6 Qf3 34.Rf1 Qe3+ 35.Kg2 |
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| Jul-04-20 | | catlover: <Jimfromprovidence> Good point. 27. d5 Qb2 is a much better reply than 27...Rc4. How to best proceed after 27...Qb2? I confess I had to use Stockfish to resolve my doubts. According to SF, 28. b6 still is possible but only leads to a +0.89 advantage. 28. d6 leads to equality. But 28. Qe7 leads to a +1.48 advantage. |
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| Jul-05-20 | | RandomVisitor: Here is another run with a better neural net configuration, designed for longer runs: Notice the final overall speed of 456 positions evaluated per second..
click for larger viewLc0_0.26.0_base:
14/37 7:38:52 12,578k <456> +7.90 24.Qe3 Bxd1 25.Rxd1 Bc7 26.Bxb7 Rb8 27.b6 axb6 28.a6 Ra2 29.Rc1 Bd6 30.Rc6 Rd8 31.Rxd6 Ra1+ 32.Kg2 Qxd6 33.Bxd6 h5 34.Qe7 Rxd6 35.Qxd6 g6 36.Bd5 Kg7 14/37 7:38:52 12,578k 456 -0.87 24.axb6 Rxd2 25.Bxd2 Bxd1 26.bxa7 Ra8 27.Rxd1 Rxa7 28.Be3 g5 29.h3 h6 30.Kh2 Qd6 31.Rc1 f5 32.d5 Ra8 33.Bc5 14/37 7:38:52 12,578k 456 -2.68 24.Qf4 Qxf4 25.gxf4 Bxd1 26.axb6 Rc1 27.Rxc1 Rxc1 28.bxa7 Bf3+ 29.Bf1 b6 30.Bc5 bxc5 31.dxc5 Rxc5 32.Bg2 Rc1+ 33.Bf1 Ra1 34.b6 Kf8 35.h3 Ke7 |
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sac: 24.Qe3
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