Wednesday
Jun092010
A Fun Puzzle From Ken Regan - With Hints
Wednesday, June 9, 2010 at 7:09PM This is the fascinating position first presented yesterday, with Black to move. (There are hints below, so if you don't want to see them, go to the original post or don't look below the diagram!)
Here are IM Ken Regan's hints:
1. Can Black get away with the pawn snatch 1...Qxb2---? White has a terrifying reply, but can Black survive it?
2. What happens if White plays h3 or Nd4 after the terrifying move? Or h3 right away?
3. Is 1...Qxb2 Black's best move in this position? Is this a case where risky Pawn-grabbing is the only safe policy?
I'll leave the comments open to anyone whose remarks aren't engine-based. Happy analysing!
Reader Comments (15)
1) After Qxb2, the scary move looks to me to be Ne7+ (which I analysed as winning when you had it as white to play in original post). Then Kh7, Bxg6, fxg6 doesn't seem to clear and with the black threat on f2, maybe white has to play Rf1. But that seems to run into the queen exchange by Qe5 (threatening h2). This might be better for black with the extra pawn on the c-file and white's static king.
2) Not looked at h3 (will do and get back to you)
3) First move I looked at for black was Bxf5 to eliminate the dangerous knight, but after Bxf5, Nf6, white has the nice move h4 which seems to be winning. Next I looked at is Kh7, but after Nd4, Bxc2, Qxc2, Kg8 then Qf5, the knight on g4 is a goner so I would say Qxb2 looks good so far. Will look more tomorrow
After 1... Qxb2 I would guess that 2. Qf8+ is the "terrifying response" since 2... Kxf8 3. Rd8# follows. However, after 2... Kh7 it isn't clear how White can effectively follow up since the Black queen can retreat ot g7 (if the knight on f5 moves) or h8 in defense. Also, White has a bishop hanging on c2 and back rank difficulties keeping his rook at home. Looks like Black "survives" if he takes the pawn since the White attach is too slow.
I sort of like Rd8+, and the idea is to play Rh8+ followed by Qf8+ and Qg7. But the problem is that the Queen covers h8. So all of the other ideas in part three seem to be blocking the long diagonal so that you can play Rh8.
I haven't looked deeper than that, but white does have back rank issues to worry about, so my first feeling is that it doesn't work since Ra1 would seem to win for black, but that was just after 5 minutes.
I could be totally wrong too :)
Upon further review, Qf8+ first is simply better in every way.
Thoughts on the initial position: White has lots of threats. For one, there's Nxh6+ followed by Bxg6, when the bishop is invulnerable due to the fork Qc4+. There's also the threat of Ne7+, eliminating the Bg6 and further exposing the black king. Finally, Black's back rank is vulnerable; if the Queen leaves, there's Qf8+ or Rd8+. I looked at this for a long time yesterday and decided I'd play 1...Kh7, avoiding the various threats. White can follow with 2.Nd4 or 2.Ne7, after which 2...Bxc2 3.Qxc2+ Kg8(g7) is better for White, but I don't see anything immediately crushing (although I would not be surprised if I missed something that is).
Maybe Black can get away with Qxb2, though. 1...Qxb2 2.Qf8+ Kh7 and now if White tries 3.Ne7, threatening Qxf7+ and mate on g8, Black can defend with 3...Qg7. What if White plays h3, though? After 1...Qxb2 2.h3, 2...Qxc2 is impossible due to 3.Qf8+ and mates. The Ng4 cannot move due to 3.Qf8+ followed by 3.Qxh6+ and 4.Rd8#. Therefore 2...Bxf5 seems forced and good after 3.Bxf5 Nxf2 (not 3...Qxf2+? 4.Qxf2 Nxf2 5.Rf1 and the knight is trapped). But what if White inserts 2.Qf8+ Kh7 3.h3? Now 3...Bxf5 is impossible, but there is another defense: 3...Qh8! 4.Qxh8+ Kxh8 5.hxg4 Rxc2 6.Nxh6 with what looks like a winning endgame for Black.
In conclusion, it looks like Black can get away with ...Qxb2; the Queen generates threats and guards key squares from b2. I doubt I'd have the stones to play it in a game, though!
i'm thinking qxb7 rb1 qf6 (qxr bxq ra1 qc2 seems to hold and there may be something better) qf8+ kh7 ne7 and the mate is hard to stop on g8.
i knew there was an oops and probably still is with this: qxb2 (not rb1 because you need the rook to end up on d7 with check) qf8+ kh2 ne7 qg7 (that's what i missed in the last post) nxg6
Eh, are we having a blind moment for some reason lol. For Q1, how is Qxb2 not a instant loss for Black.
2. Qf8+, Kh7 3. Q7#. The knight's g7! O^o
Oh f-it, I'm being blind, nvm lol. Teach me not to jump the gun. Neat trick!
Good start, fellas! The "terrifier" is meant to be 2.Qf8+. In reply specifically to Dan Malkiel, after 1...Qxb2 2.Qf8+ Kh7 3.h3 Qh8 4.Qxh8+ Kxh8, White has a strong Zwischenzug (in-between move, while still attacking Black's Knight). Look instead at Move 3 for a "Zwisch" of Black's own, and ditto after 1...Qxb2 2.h3.
After the "safe" 1...Kh7, you're right to consider moves by White's Knight---look at some other ones too...
Sorry for the triplet, Dennis, but I thought I should at least contribute something substantive. Feel free to delete earlier posts (or not to show my patzer-like first impressions) :P.
The most interesting continuation seem to be what happens after 1...Qxb2 2. Qf8+, Kh7. Seems people already looked at it, so this makes it easier for me hehe. The queen, bishop and rook can't move at risk of dropping material or mate so that leaves the knight. (Ok, h3 is possible, but I can't follow that so if that's the best continuation... then I've no hope...)
Ne7 threatens Qg8 mate but Black has the Qg7 retreat if nothing else so he'd have gotten away with the pawn grab. Or is there a tailend sting somewhere that I can't see? Dan's Nd4 seems to be the best other choice and I think he got most/all of it! It keeps the Black queen from coming back and defends the c2 bishop so Black has to take back with the bishop instead:
3.Nd4, Bxc2 (I tried to find his Qxc2+, but that's an illegal move, I assume he meant Qxf7!) 4. Qxf7+, Kh8. I thought wrongly(again) that White had a win with 5. Rd8#!!! but then I saw that the knight's blocking the way. White doesn't have time for anything but a check or mate threat since his rook is hanging and mate's being threatened on the backrow. I tried Ne6 and Nf5 but that doesn't seem to work since g7 is again covered by the Black queen. So best I got was draw by repetition for White.
1...Qxb2 2. Qf8+, Kh7. 3.Nd4, Bxc2 4.Qxf7+, Kh8 5. Qf8+, Kh7 6. Qf7+ etc...
Well, is a draw for white good enough a refute for Qxb2?
Ken: Of course - after 1...Qxb2 2.Qf8+ Kh7 3.h3 Qh8? 4.Qxh8+ Kxh8 5.Bb1 wins for White. Black must play 3...Ra8 4.Qxa8 (4.Qc5 Ra2 =/+) Qxc2 5.Rf1 (5.Qf3 Ne5 -+) Qxf5 6.hg Qxg4. White will win the c-pawn and a draw seems likely. If White goes for 2.h3, I missed 2...Qe5, which looks good for Black.
It looks like Black has to take the pawn because my original intention 1...Kh7? simply loses to 2.Qd4.
What a rich position!
Oops, no it doesn't! 1...Kh7 2.Qd4? Qxb2 with the x-ray. I still don't see what's wrong with 1...Kh7.
Good, you (Dan and all) found the flashy---and needed---reply 3...Ra8! (after 1...Qxb2 2.Qf8+ Kh7 3.h3).! It is totally fine to assess the resulting position as a draw, even if Black loses the c-pawn. Which is not a given---Black sometimes has tricks with ...c6! in positions where Qxc6 is met by ...Be4 with a fork on g2.
This is one of four interesting qualitative decisions that animate this position along with the tactics. The second is reached after 1...Qxb2 2.Qf8+ Kh7 3.Nd4 and your 3...Bxc2. Here I must admit my own assessment was just "Qxf7+ and Nxc2 and Black is gonna get mated"---and I didn't even include this in the PGN file I sent Dennis. It's not that bad for Black, and White has to be accurate, but look a little further and see if you agree at least with a verdict that Black is in unwelcome trouble. A different Black reply to 3.Nd4 leads to the last exchange of flashy moves I've found in the position---and these two have a nifty symmetry!
The third comes up after 1...Kh7. Try 2.Ng3! First see what happens if Black plays 2...Bxc2? So Black's Bishop must stand its ground on g6, and needs support. Thus 2...Qb6 3.Bxg6+ Qxg6, then 4.h3 Nf6, and what do you think about the position?
The fourth occurs after a line that wasn't included in a hint, but now that you've found the idea Bb1! in one thematic line, try it earlier in others. Comparing this to the third is the issue my questions in "hint 3." are driving at.
Thanks for the props, and enjoy further! ---Ken R.
This was fun.