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| Jul-01-10 | | Once: It was a little after midnight, the witching hour, when the four of us met again in the drawing room of Lord Symmond's mansion. The night air was cold and clear, and a full moon shone through the casement windows. We had all come prepared. Father Quinn had brought holy water and an ornate gold crucifix. The Texan had come armed with a Winchester rifle and a pair of six-shooters on his hips. As Lord Symmonds had instructed me, I had brought a lamp and a pitchfork from the stables. Our mysterious guide, Doctor Van Helsing, spoke first. "Good, good, I am glad your courage has held. Tonight you will need all of it. Tonight we must hunt and kill a vampyre." "How can we kill something that bullets can't scratch?" asked the tall and broad-shouldered Texan. Van Helsing drew out a dozen wooden stakes from a leather valise. "Patience, patience. A vampyre's attack can be deadly, but it is also predictable. And in that predictability we have a chance to strike back." "How", asked Father Quinn, his normally sonorous voice a quiver of fear and nervousness. Van Helsing explained: "This is how the vampyre strikes. First, he immobilises his victim with Bxh7+, like a dagger strike to the jugular. Then he unleashes the hounds of hell with Ng5+. Finally, he pounces, like a bat in the night. With Qh5, he threatens a deadly mate on h7." "It sounds terrifying," I heard myself say.
"It can be enough to stop the heart of the bravest soul," said Van Helsing. "But the Vampyre has two weaknesses that we can exploit. First, he must pause after Qh5 before delivering the fatal blow to h7. That can give us just a brief second to act. And, secondly, his attack must fall on h7. If we can bring our defences to bear on that spot, the beast may yet be repelled." "How might we defend h7?" asked the Texan.
"A knight on f8 might do it, or on f6," said Van Helsing calmly. "Or better yet, a queen check on a5 while the vampyre is about to strike, followed by a swift leap to f5. From there, h7 would be covered and the beast repulsed." It sounded like the craziest of plans, but in that dark hour we had no other way of fighting the dark terror that had bought such horror to this quiet part of England. And so it was that the four of us gathered our weapons around us, and stepped out into the night... |
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Jul-01-10
 | | FSR: Huh, I have never seen that defensive idea before. Years ago, I spent a lot of time studying Vukovic's classic "The Art of Attack in Chess", which analyzes the Bxh7+ sacrifice in depth. I don't think he mentioned the Qa5+ to Qf5 defense. Good to know. |
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Jul-01-10
 | | scormus: Is this a case of <CG geeks bearing grifts>. After yesterday I try to be a bit more careful and play it through. The only move I would look at is 11 Bxh7+, and look for a #. Can the BK escape after 11... Kxh7? After 12 Ng5+ there's no playable way back so 12 ... Bxg5 13 hxg5+ Kg6. Then 14 Qh5+ Kf5 15 g6+ Kxf4 (or 15 ... Ke4 16 Qf3+ Kf5 17 Rh5+ Kxg6 (or ... Kf6 18 Bd6+ etc) 18 Qg4+ Kf6 19 Qg5#) 16 g3+ Ke4 17 f3+ Ke3 18 Rd1 and B avoids # only by ruinous sacs. I expect there are quicker ways to secure the win (if not the #) .... and I maybe missed something anyway I suppose B could last out longer with 11 ... Kb8 but not much fun in that <Once> I hope you're doing better than the BK here |
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Jul-01-10
| | scormus: :O and I was only joking about geeks bearing grifts |
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| Jul-01-10 | | TheaN: <David2009: ...(Bojkovic vs Zhao Xue 2008, 40?) and then play it out against Crafty. Did you just lose like me?> Well, no, but that depends on what you consider the solution. I missed yesterday (and today), after 40.Qg5 Crafty knows mate is imminent so plays 41....Qc1†, after 42.Qxc1 Bxf6 43.Qxc6 Bg7 44.Rxg7 Kxg7 45.Qd7† Kh6 46.Qe6† Rg6 47.Qxg6†  I simplified enough to know I would win :). |
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| Jul-01-10 | | Marmot PFL: Usually its the bishop coming to f5 that refutes the Bxh7+ sac, but here the queen does it. Yes, I missed that detail, but it is still early morning for me. |
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Jul-01-10
 | | chrisowen: For one too blahzay blahzay. Try angle Qh5 Ng5 h4 is crappy after Qa5+. And do the math calculate it c3 Qf5 keeps the piece. Rise French Canadian East is in the house oh my god danger. |
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| Jul-01-10 | | SufferingBruin: <At least I didn't fall for this "obvious" sacrifice twice.> If they posted this tomorrow, I'd still fall for it. :) It was written of Tal that he would engage in sacrifices on a whim, just to get the damn initiative. He was romantically described as an artist, a refreshing contrast to the intensely scientific approach of Botvinnik. And this is why we rank amateurs occasionally dip our toes into the waters of Bxh7, only to realize the waters are tainted with radioactive waste that will eat through your foot. |
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| Jul-01-10 | | StevieB: I was thinking of the other bishop.
11.Bh6 gxh6
12.Ng5 hxg5
13.Qh5 qa5+
14.Kd1 h6
15.Qxh6
Then, what would black do to stop the white queen from going to h7 for the mate? |
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| Jul-01-10 | | gofer: Well, lets go for the throat.
1) How about a simple queen attack?! 11 Qe4 Qa5+ 12 Bd2 Qf5 13 Qxd4 wins a pawn, but not much more and we want so much more! 2) So how about throwing the bishop at the problem. 11 Bxh7+ Kxh7 12 Ng5+ Bxg5 13 hxg5+ Kg6! Hmmm
not as cut and dried as I thought, so we have to trap the king. Lets start by getting another
bit in play 14 o-o-o, but this seems way too much for a Thursday! 3) How about throwing the knight in instead! 11 Ng5 ... Now the nice thing about this is it opens
the d1-h5 diagonal for the queen, it attacks h7 and it is immune from capture because opening up the
h file is suicide! Also we have the added bonus of Nxe6 fxe6 Qxe6+ at some point if we should ever
choose. But yet again black has a simple defense g6, now opening up the h file is much more difficult.
Also, before playing g6 black gives check on a5 and stops Ra1 from getting into the game. 4) How about the other bishop! 11 Bh6 gxh6 12 Qe4 looks unstoppable, but... 12 ... Qa5+ 13 c3 Qf5 and we have just lost a bishop
for not very much.
I now think this is an evil puzzle and could be a "spoiler". So I think my move would be castle queenside
and then play line 2 above...
11 o-o-o ...
Time to check... |
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| Jul-01-10 | | Patriot: I fell right into it, not seeing the familiar "check and defend" idea. Knowing familiar patterns make us stronger players, but it's easy to get into trouble if we assume that it's a winning pattern without proper calculation. On the "Chess Tactics Server", you are practically forced to make these kinds of assumptions if you expect a higher rating. Essentially you need to solve the problem, which could involve 5 moves, in about 3 seconds to improve in rating. OTB, I would never play most of those combinations in 1 or 2 seconds unless I'm in severe time trouble. But solving puzzles that quickly usually works only for the fact that it is a puzzle where a win is usually there. OTB you never know for sure until you roll up your sleeves and do the work to make sure the combination really works and that there are no zwischenzugs. Still, doing tactics that quickly is a good idea for learning pattern recognition which helps OTB. I am not sure if I would have seen this during an actual game, but the fact this is a puzzle and the assumption there is a win probably had some impact on my mistake and probably most of the kibitzers who missed the defense. However it is true that the player himself (whose rating is 2499!) made the same mistake. |
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| Jul-01-10 | | David2009: <TheaN: <David2009: ...(N Bojkovic vs Zhao Xue, 2008, 40?) and then play it out against Crafty. Did you just lose like me?>
Well, no, but that depends on what you consider the solution. I missed yesterday (and today), after 40.Qg5 Crafty knows mate is imminent so plays 41....Qb1†, after 42.Qxb1 Bxf6 43.Qxc6 Bg7 44.Rxg7 Kxg7 45.Qd7† Kh6 46.Qe6† Rg6 47.Qxg6† I simplified enough to know I would win :).> Second time around against Crafty I played 40 Qg5 Rg8 41 Ne5 Qb1+ 42 Kh2 (I am fully prepared for all back rank checks: I have worked out that Black has no time to checkmate me on g2) 42...Qxb7 0-1 |
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| Jul-01-10 | | David2009: P Charbonneau vs H A Hussein, 2008 <gofer> and others have suggested 11 O-O-O threatening Bxh7+. Against Crafty End Game Trainer, this leads to a draw by perpetual check - unless you can find better. In-line link: http://www.chessvideos.tv/endgame-t...
CraftyEGT does not permit castling: so move the K from d2 to c1 to complete the castling move. Similarly, Crafty defending draws by perpetual check if White starts off 9.h4 http://www.chessvideos.tv/endgame-t... <Once:> yours are really excellent and enjoyable contributions. Keep on posting! |
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| Jul-01-10 | | kevin86: Here is a case where the magician was bitten by his own trick. Black's sharp counterthrust give the game an O'Henry finish. |
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| Jul-01-10 | | gropek: White to play
P Charbonneau vs H A Hussein
11. ?
Difficulty : Medium
Black is a pawn up, but white has better placed pieces, and almost all pointing to the kingside. Also, some of
black's pieces are not there to help, and can't get to the kingside easily. Therefore, white should try an attack
on the king!
Candidates 11. Bxh7+ / 11. Qe4 / 11. Ng5 / 11. Bg5
Let's check first 11.Bxh7+, which sounds more forcing. Now, black can refuse or accept the sacrifice. Normally refusing is way worse, but... Let's check this line. 11. Bxh7+ Kh8
12. Ng5 (In this line, the queen can come easily to h5, and I can't see any good way to prevent that) So, black is pretty much losing in this position. Lets see the main line, with the accepted sacrifice. 11. Bxh7+ Kxh7
12 Ng5+
Now the lines with king moving.
(1) 12 ... Kh6 13 Nxe6+ Winning the queen.
(2) 12 ... Kg6 13 h5+ Kf5 14 Qe4+ Kg4 15 f3#
(3) 12 ... Kh8 13 Qh5+ Kg8 14 Qh7#
(4) 12 ... Kg8 13 Qh5
(4.1) 13 ... Re8 14 Qh7+ Kf8 15 Bd6+ and loses material and after get mated. (4.2) 13 ... Bxg5 14 hxg5 f6 15 g6 and mate is unstoppable. Looks like if the king moves, he dies.
Finally , lets see the lines with bishop capturing first. 12 ... Bxg5 13 hxg5+
(1) 13 ... Kg8 14 Qh5 with same ideas.
(2) 13 ... Kg6 there is checkmate too. but i wont calculate, as im too lazy now. Okay, if I didn't overlook anything, 11.Bxh7+ is the answer for today! Time to check.
---
Well, too bad for me... I guess I felt into the same trap as Pascal did in the game. |
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| Jul-01-10 | | njchess: This was a fun puzzle. Like many, I explored 11.Bxh7+. But, without an obvious mate sequence, I wasn't prepared to launch an attack with my king exposed. As it turned out, 0-0-0 is probably the best move for White. Initially, when I looked at the position, it resembled a Sicilian type of layout, and Black always has the option of Qa5+ or Qb6 in that type of position. Ultimately, that was why I discarded Bxh7, which turned out to be the game line. |
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| Jul-01-10 | | Mace: <dzechiel> Haha, I had to do a double take after seeing the 0-1. I was pretty sure that black had just forfeited after a spite-check, guess it was more than that. <dzechiel> I was looking at this combo too:
11.Bxh7+ Kh8 12.Ng5
12...Qa5+ 13.Bd2
but black can follow with ..Be7
14.Qh5 Nf6 which completely counters white's attack
I'm at a loss, every attack I see is countered pretty hard. Has anyone gotten it yet? |
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| Jul-01-10 | | cracknik: OK, it's tricky. What's the solution though? |
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| Jul-01-10 | | dhotts: Did anyone notice that BLACK won this game showing that 11.Bxh7 is a failure? Because after 13...Qa5+ there is 14...Qf5 forcing the Black win. So what is the puzzle answer for White to play and win? Or is this a puzzle mistake? |
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| Jul-01-10 | | zooter: Ok, The only weak black spot seems to be h7. So we start with 11.Bxh7+ Kxh7 (no point refusing the sac) 12.Ng5+ and it's all over whether black takes the knight or not Time to check |
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| Jul-01-10 | | Once: <dhotts> <cracknik> This is what is known as a spoiler. It looks as though white has a stock greek gift combination starting with 11. Bxh7+. But this is one of those situation where the combination doesn't work. By playing 13....Qa5+ followed by 14...Qf5, black defends h7, stops the mate and pockets the bishop that white sacrificed. So the solution today is not to play 11. Bxh7+, but to opt for something a little more sensible. 11. 0-0-0 would be fine. Chessgames.com throws us these little spoilers every now and again to stop us from becoming too complacent. Otherwise we could fall into the trap of thinking that every combination works perfecly. For the full story, read from page 1 of the kibittzing and all will become clear. |
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| Jul-01-10 | | dhotts: <once> thanks for the great explanation! |
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| Jul-01-10 | | zooter: groan, fell for it again. That's the second time! |
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| Jul-01-10 | | Eisenheim: even though I specifcally told myself not to fall for it, since I did yesterday, i still fell for bxh7+ today. du-oh! |
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| Jul-01-10 | | Patriot: <Mace> <I was looking at this combo too: 11.Bxh7+ Kh8 12.Ng5
12...Qa5+ 13.Bd2
but black can follow with ..Be7
14.Qh5 Nf6 which completely counters white's attack>After 13...Be7 14.Bxa5 wins. I don't think black can afford to play 11...Kh8. |
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