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Later Kibitzing> |
| Mar-02-13 | | gofer: The choice seems to be between Nxh7 and Bxg6. I think Bxg6 is more forcing. It forces the rook trade-off at which point black walks into
a royal-knight-fork or loses three pawns in gaining the bishop, not "done and dusted", but if white can keep Q+R+N and get all three around
the black king then sparks are sure to fly!
<27 Bxg6 ...>
Avoiding the rook exchange just loses two pawns for nothing... 27 ... Rd4 28 Qh5 h6 29 Nf7+ Kg8 30 Nxh6+ Bxh6 31 Qxh6 Qc7 32 Rxd4 exd4 33 Re1 with Qg5 and Re7 to follow... <27 ... Rxd1+>
<28 Rxd1 ...>
Black cannot allow Qh5 (as seen above), so the Bishop sacrifice looks as though it has to be accepted! <28 ... hxg6>
<29 Rxd6! ...>
30 ... Qxd6 31 Nf7+ Kg8 32 Nd6 
<30 ... Qc7>
<31 Rxg6 ...>
Black has to find a defense to 31 ... Qh5+ 32 Kg8 Qh7+ 33 Kf8 Ne6+ , but nothing is obvious! 31 Re8 Qh5+
32 Kg8 Qh7+
33 Kf8 Rf6+!
34 Bxf6 Qxc7
35 Bxg5 Qxa5
~~~
Yep! Defense is very difficult!
<pojtr:> What's the refutation of 27.Qg4 ? 27 Qe4/Qg4 just aren't as forcing.
Black has lots of options;
27 Qg4 Rd4
28 Qe6 Rf8
29 Nxh7 Rxd3
30 Nxf8 Rxd1+
31 Rxd1 Bxf8 |
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| Mar-02-13 | | nateinstein: I would be interested in what black's defenses are for 27. a4 (with the ideas of 28. Nf7+ and 29. Bc4 if black's b pawn loses control of c4. |
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| Mar-02-13 | | David2009: Naiditsch vs I Sokolov, 2012 White 27? White can give up N x B for RPP in the sequence 27.Nxh7 Rxd3 28.Qxd3 Kxh7 29.Qxd6 Qxd6 30.Rxd6 but Black gets good counter-play starting 30...Nc4 31.Rd7 Rxa2 and a draw looks likely. 27.Qe4 first runs in to Rd4. 27.Qf3 allows Rf8. Not seeing a combination I would go with Be4 in OTB play. Time to
check:
===
Missed it completely. Here's the puzzle position
click for larger view
set up on Crafty End Game Trainer, interactive link:
http://www.chessvideos.tv/endgame-t...
The prudent robot declines the sacrifice preferring to lose two Pawns. Here's a link to the position two moves later:
http://www.chessvideos.tv/endgame-t... In reply to 29.Rxd6 the robot plays Qxd6 when the game might continue
29...Qxd6 30.Nf7+ Kh7 31.Nxd6 Nc4 32.Nxc4 bxc4 33.Qxc4 e4
to reach
click for larger view
whn the win is no doubt there but is not trivial. Enjoy exploring! <pojtr: What's the refutation of 27.Qg4?> Play it out using the first interactive link. It's what Crafty End Game Trainer is for! |
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Mar-02-13
 | | paulalbert: Could not visualize as far as all the Q forks set up at Rxd6 and thereafter, so only glanced at Bxg6 without giving it proper consideration. First looked at Nxh7 but at least saw this did not accomplish much after Rxd3 response. Frustrating not to be able to see even the main ideas, let alone all the variations. |
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| Mar-02-13 | | kevin86: This one is a little deep for me...and there's sharks! |
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| Mar-02-13 | | kevin86: and there are forks in the water! |
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| Mar-02-13 | | bengalcat47: To borrow terminology used in checkers, "Beware of tricks, traps, and shots!" |
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Mar-02-13
 | | Jimfromprovidence: I though that black might play 28...d5?! instead.
click for larger view That protects the d pawn as it puts white's bishop en prise. But after 29 Bxh7 Qf6 white is up a pawn and threatening to take a couple more, so maybe there is not much difference in the value of the two moves.
click for larger view |
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Mar-02-13
 | | LIFE Master AJ: Very cool.
I thought that the solution 27.Nxh7, although I only spent around 1-2 minutes on the problem, so I missed/messed it. 27.Bxg6!! VERY sweet combine ... based on the Knight fork. (I had looked at BxP/g6 for a bit, but dismissed it. To be honest, I did NOT see the RxP/d6! move, that was the core of the whole combination.) Good problem / POTD. Another lesson in Knight forks and the power of this piece. Thanks for the POTD, CG. |
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Mar-02-13
| | LIFE Master AJ: I wonder how much of this was prepared at home ... |
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| Mar-02-13 | | Marmot PFL: Pretty combination. I knew the knight sac didn't work but couldn't decide if the bishop sac did or not. Offhand they seemed like the only major candidates. |
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| Mar-02-13 | | Patriot: Black is a pawn up.
With the rook on d5 undefended and white's rook x-raying through to it, I looked for a way to take advantage of this by moving the bishop with tempo. The only problem is that black can almost always play ...Rxd1+. One idea...
27.Nf7+ Kg8 28.Bc4 Rxd1+ 29.Qxc1 Nxc4 30.Qd5 Kf8 (avoiding smothered mate). 30...h6 is another way. This doesn't look convincing.
Another idea...
27.Nxh7
27...Kxh7 28.Bxg6+ Kxg6 29.Rxd5 or perhaps 29.Qe4+ first. This imbalances things a bit which is probably what white wants. 27...e4 28.Qxe4 Rd5 29.Qxg6
27...Rxd3 28.Qxd3 Kxh7 29.Qxd6 looks nice for white.
I would go with 27.Nxh7, which if nothing else a threat exists to take on g6 as well. |
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| Mar-02-13 | | Patriot: <<morfishine>: 29.Rxd6 was sweet> Yes it is. I actually did calculate 27.Bxg6 but missed this point. <LMAJ> I also went with 27.Nxh7, missing the key behind 27.Bxg6 (the fork). After 27.Nxh7 e4 28.Qxe4, I missed 28...Rf5 instead.
Nice problem! |
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| Mar-02-13 | | Patriot: Also, in my 27.Nf7+ line, 30...Kf8 is a big mistake--31.Ng5! Houdini suggests 30...Bf6 (best) or 30...h6  . |
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| Mar-02-13 | | sushijunkie: Not sure I would have found 29. Rxd6, and the engine says it's the only non-losing move, so I can't even take partial credit for finding 27. Bxg6 & 28. Rxd1. Booooooo, me. |
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| Mar-02-13 | | agb2002: White is a pawn down.
The light squares around the black king look weak. This suggests 27.Nxh7, but after 27... Rxd3 (27... Rxh7 28.Bxg6+ Kxg6 29.Rxd5 looks bad for Black) 28.Rxd3 Kxh7 29.Rbd1 Bf8 Black seems to resist. Another option is 27.Qg4, threatening 28.Qe6 and 28.Qh4, but 27... Rf8 covers f7 and threatens f2. For example, 28.Qh4 h6 29.Bxg6 Rxd1+ 30.Rxd1 Rf4 31.Nf7+ (31.Qh5 Rxf2; 31.Qg3 hxg5) 31... Kg8 32.Nxh6+ Bxh6 (32... Kh8 33.Ng4+ Kg8 34.Qh7+ Kf8 35.Nh6 Qxf2+ 36.Kh1 Bxh6 37.Qxh6+ Ke7 38.Qg7+ and the attack looks winning) 33.Qxh6 Qxf2+ 34.Kh1 Qh4 seems to hold. Finally, 27.Bxg6, further weakening the light squares, deserves consideration, 27... Rxd1 28.Rxd1: A) 28... hxg6 29.Rxd6
A.1) 29... Qxd6 30.Nf7+ Kg8 31.Nxd6 + - [Q+P vs R+B]. A.2) 29... Qc7 30.Rxg6 (threatens 31.Qh5+ Kg8 32.Qh7+ Kf8 33.Ne6+) A.2.a) 30... Re8 31.Qh5+ Kg8 32.Qh7+ Kf8 33.Rf6+ Ke7 (33... Bxf6 34.Qxc7) 34.Qxg7+ Kd8 35.Ne6+ Rxe6 36.Rf8+ Re8 37.Rxe8+ Kxe8 38.Qxc7, etc. A.2.b) 30... Ra6 31.Rxa6 (31.Qh5+ Kg8 32.Qh7+ Kf8 33.Ne6+ Rxe6 34.Rxe6 Qc1+ 35.Kh2 Qf4+, perpetual) 31... bxa6 (31... Qc1+ 32.Kh2 Qxg5 33.Rxa5) 32.Qh5+ Kg8 (32... Bh6 33.Qe8+ Kg7 (33... Bf8 34.Qxf8#) 34.Ne6+ Kf6 35.Nxc7, etc.) 33.Qh7+ Kf8 34.Ne6+ wins the queen. A.2.c) 30... Qe7 31.Qh5+ Kg8 32.Qh7+ Kf8 33.Ne6+ looks crushing. A.3) 29... Qc5 30.Rxg6 looks similar to previous lines. For example, 30... Ra6 31.Qh5+ Kg8 32.Qh7+ Kf8 33.Qxg7+ and mate soon. A.4) 29... Qa7 30.Rxg6 is again similar to previous lines. A.5) 29... Nc6 30.Rxg6 is again similar to previous lines. B) 28... Rf8 29.Nxh7 removes the last pawn and makes the attack stronger. For example, 29... Rf4 30.Ng5 Rh4 31.Rxd6 Nc6 32.Re6 Qc5 33.Re8+ Bf6 34.Ne6 is disasterous for Black. |
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| Mar-02-13 | | agb2002: <Jimfromprovidence: I though that black might play 28...d5?! instead.> I didn't even consider 28... d5 because of 29.Bxh7 and 30.Qh5. For example, 29... Qf6 30.Qh5 Bh6 31.h4 d4 32.Rd3 Rf8 33.Rf3 Qg7 34.Rxf8+ Qxf8 35.Bg6 with the double threat 36.Nf7+ and 36.Ne6. |
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Mar-02-13
 | | chrisowen: Giddy up ride a lion it seem like for together,
binded in godaffy 27.Bxg6 ducked out of the way it is double in daccord 27...Rxd1+ clutching in bull it shine in redeploy it straws in engaging 28.Rxd1mercurial one together it snide either in matching 28.hxg6 boxed pawn seems it hope in energetic, 29.Rxd6! indefinately yo uber man to therescue 29...Qc7 cordial one 30.Rxg6 look it is cream in give rocket to the dutiful crums it rook geoffrey also g5knight and matilda I queen I rite in really it scrape in flew over 30...ra6 ai now it I see grace, in angelic arm a 31.Rxa6 effected rooftop alm a 31...ba6 tame in band of merry men eg 32.Qh5+ age, the threat in mind would get ok 32...kg8 ate its cc for get 33.Qh7+ and fin kingf8 hoodwink knighte6+ at corner collect, i think eg back to d6 arm in good game rural one chin 34...ke7 35.Nxc7 and yeah i flipflop in knight bg7 honours it h7queen sitter in knightc7 lop. |
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Mar-02-13
| | chrisowen: Engage heeded for wall it is be in the vale you at, rook in d6 wheel over h5 er backed time thod in carry it honour in clinch a grin seems it horde in black rook5 rag on ha tended 26...Nc4 keeps it the piece in bd3 light however get, he dog in no time light a kipper b6 tie down a beat in marble it stone g6 in tip you late again g6 i think it skulking h8 nincompoop its peach in rookd1 having, calms it rookd5 in tie d4 own ie champing light or,
c4 hah b4 in bad b8 lip in rook queen balled it shackle in group knight parlez it pick in purple g5, patch angle row in cheat rifle as it layer in h5 call i flower h7 it satz in corroborate a king for, the day in alight rookd1 reign d3 in jack an g6 ill ie pan pipeline d6 coil in exactly it so black drubbing boot in d1 er bending light tumped a breath in go durable d6 might aim sitter banged to, right a wrap in gadzookd3 to g6! |
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| Mar-02-13 | | AndrewMD: My first gues was 27. Bxb5. How was it? |
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Mar-02-13
| | Jimfromprovidence: Has anyone noticed that the moves 31 Rxa6 and 32 Qh5+ do not seem to be transposable, which is a kind of a nice wrinkle to this puzzle? |
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| Mar-02-13 | | bharat123: My first try was 27.b4 Nc4 28.Nf7+ Kg8 29.Bxc4 Rxd1 30.Rxd1 Bxc4 31.Qxc4 (Threatening mate followed by Nh6+) 30...h5 31.Rxd6 Qa7 32.Nxe5+ Kh7 33.Rxg6(Threatening mate followed by Rxg7. Also black cannot play Bxe5 which leads to mate by Qf7+). White has attack and material. I thought that I solved it very quickly. But black can avoid the whole variation simply by 27...Nc6. |
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| Mar-02-13 | | bharat123: Typing error. 30...bxc4 instead of Bxc4. |
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Mar-02-13
 | | FSR: I saw it through 30.Rg6, but then hallucinated a defense for Black. |
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| Mar-03-13 | | agb2002: <Jimfromprovidence: Has anyone noticed that the moves 31 Rxa6 and 32 Qh5+ do not seem to be transposable, which is a kind of a nice wrinkle to this puzzle?> I only noticed the possibility of perpetual, line A.2.b, but it seems you're right because after 31.Qh5+ Kg8 32.Rxa6 Qc1+ 33.Kh2 Qf4+ the f-pawn is defenseless so that 34.g3 is useless and Black achieves perpetual. |
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< Earlier Kibitzing · PAGE 2 OF 2 ·
Later Kibitzing> |
Kibitzing
sac: 27.Bxg6