| Dec-01-16 | | crystalpauper: Rook sac at f7 yields big returns if accepted. |
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Dec-01-16
 | | Big Pawn: An easy one. Rxf7 keeps the tempo and then Ne5+ is effective because the white Queen cuts off the third rank and coordinates with the Knight on the light squares. |
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| Dec-01-16 | | Doniez: I got it very quickly. But most important is that Magnus Carslen is World champion again and, in my humble opinion, it's unfair that the most important match is decided after only 12 games and then on a 4 rapid game tie break. Anyway, congratulation to the champion. |
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| Dec-01-16 | | patzer2: Should have been easy for me, but I stopped calculating after 35. Rxf7 Kxf7 36. Ne5+ Ke7 37. Nxg6+ Kf7 38. Kg8  (diagram below)
click for larger viewHad I looked a few more moves ahead here (diagram above), I would have seen 37...Kg7 38. Qxg6+ Kh8 39. Nf7#. Instead, for today's Thursday puzzle, I tried a pin with 35. Rb7?! (diagram below) 
click for larger viewIn this position (diagram above) after 35. Rb7?!, the game fizzles out to level after 35. Rb7?! Qa8! 36. Rxb6 Nxb6 37. Qxa8 Nxa8 38. Rd8 Nb6 39. Bd6 Nd7 40. Rxd7 Rd1 41. Bxf8 Rxd7 42. Bxh6 Re7 43. Be3 = (0.02 @ 25 depth, Deep Fritz 15). P.S.: For a Black improvement, instead of 19...Nh7 allowing 20. Nxc4  , the computer suggestion 19... Nfxd5!? 20. exd5 Rxb2 21. Qd1 (21. Qxc4 Rb4 22. Qc2 Bxa1) 21... c3 22. Nc4 Qb8 23. Bd3 Re8 = (0.00 @ 21 depth, Deep Fritz 15) looks good for Black. |
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| Dec-01-16 | | saturn2: The first two moves were quickly seen then there are some variations to calculate depending on where the king moves after Ne5+ |
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Dec-01-16
 | | agb2002: White has a rook and the pawn for a bishop and a knight. White has Rxf7 and Ne5.
In the case of 35.Rxf7:
A) 35... Kxf7 36.Ne5+
A.1) 36... Kg7 37.Qxg6+ Kh8 38.Nf7#.
A.2) 36... Kg8 37.Qe6+ Kh8 (else 38.Qxg6+ as in A.1) 38.Nf7+ wins the queen. A.3) 36... Ke7 37.Nxg6+ Kf7 38.Ne5+ Ke7 (else as above) 39.Bh4+ wins the queen. B) 35... Ne7 36.Rxd8 wins (36... Nxc6 37.Rdxf8#). C) 35... Qc8 36.Qxg6+ and mate next. |
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| Dec-01-16 | | stacase: Got it move for move. Pretty easy Thursday for that to happen (-: |
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| Dec-01-16 | | patzer2: Correction: I stopped calculating after 35. Rxf7 Kxf7 36. Ne5+ Kg8 (diagram below)
click for larger viewHad I looked a few more moves ahead, I might have seen 37. Qe6+! Kg7 38. Qf7+ Kh8 39. Nxg6#. |
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| Dec-01-16 | | gofer: White is a pawn up and an exchange up, but a piece down, so materially losing.
However, white has a rock solid defence and black really doesn't. <35 Rxf7 ...>
If black refuses the rook sacrifice white not only threatens Qxg6+ mating, but black will also be materially losing, so really there is no point refusing the sacrifice! <35 ... Kxf7>
<36 Ne5+ ...>
The black king must find a good square to run to and there are only
three choices; two of which result in a quick mate! 36 ... Kg7
37 Qxg6+ Kh8
38 Nf7#
36 ... Ke7
37 Nxg6 Kf7
38 Ne5+ Ke7 (Kg7 is covered above and Kg8 is discussed below)
39 Bh3+ Nf6
40 Bxf6#
So at some point the black king is going to have to run to g8. <36 ... Ke7>
<37 Nxg6+ Kf7>
<38 Ne5+ Kg8>
<39 Qe6+! ...>
click for larger view37 ... Kh7/Kg7 38 Qxg6+ Kh8 39 Nf7#
<37 ... Kh8>
<38 Nf7+ ...>
click for larger viewOkay, so we have won the black queen, but what do the machines
say is the number of moves to mate?! What is the cleanest kill?! |
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Dec-01-16
 | | perfidious: Interesting that three of the last five POTD have featured Deysi Cori, with her finally coming up winner today--though she was facing a redoubtable opponent the first two times out in this series. |
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| Dec-01-16 | | Cheapo by the Dozen: I was thinking much the same as <perfidious>. Somebody obviously took a look at her games ... |
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| Dec-01-16 | | saturn2: I did not know her before but having looked at her pic was a nice experience. The middle game of today's puzzle game was rather complex and the combination started already at move 34 Nxf7. |
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| Dec-01-16 | | morfishine: <35.Rxf7> followed by <36.Ne5+> oughta do it |
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| Dec-01-16 | | Muttley101: @patzer2: I like the honesty of your analysis and thoughts about what you see in the position, and what else was there to discover. This is the way to improve for sure- good job!- and I like looking through your variations to compare them with my analysis- I missed 37. Qe6+! when I looked at the orignal position- thank you! (Note to others who provide considerable thoughts and analysis- too many to mention :) ) |
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| Dec-01-16 | | johngalt5579: Ne5 looks winning to me. |
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| Dec-01-16 | | catlover: This game is won by a beautiful combination by the Peruvian WGM. Bien hecho, Deysi. |
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| Dec-01-16 | | YetAnotherAmateur: I found the accepting line (the one actually played) easily enough. Then I tried to look for declines, and what's really striking in this position is how completely impotent black's pieces are: - Any move of the queen loses her without compensation. - The Nd5 is pinned against the queen.
- Which leaves the Nb6 stuck defending d5.
The only moves that don't seem to make things worse are: Bg7, Ra1, Rb3, Rb4, Rf1, Bb4, Ba3. All of which allow Qxg3+ with mate to follow. |
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Dec-01-16
 | | PawnSac: < perfidious: Interesting that three of the last five POTD have featured Deysi Cori, with her finally coming up winner today--though she was facing a redoubtable opponent the first two times out in this series. > yes i was thinking exactly the same thing. Good to see a win for her. |
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Dec-01-16
| | PawnSac: the exchange sac 25...Rxe2?! certainly wasn't necessary. Yes white already has a nice edge, but ..Re6 looks better. After 26.Qxc5 Be4 black is skating on thin ice, but c'est la vie |
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Dec-01-16
 | | kevin86: White's open lines end this one. |
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| Dec-01-16 | | David2009: D E Cori Tello vs D Real Pereyra, 2016 White 35?
click for larger view
I couldn't solve it (the morning after the world championship before) so
I looked it up. After 35.Rxf7 Bd6! postpones defeat by giving back a piece. Crafty End Game Trainer link: http://www.chessvideos.tv/endgame-t.... Enjoy winning the endgame - if you can! Massive congratulations to anyone spotting 35.Rxf7 Bd6! without the aid of an engine - I did NOT. |
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Dec-01-16
 | | Longview: I am pleased that watching good chess for three weeks has given me my first Thursday solution in a long time! |
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| Dec-01-16 | | R4f43l L3 M4550n: It's very kind of CG to present a beautiful combination from Deysi Cori just now, in the sequence of two other puzzles in which she was losing... Yes, she is pretty, young and great player! |
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Dec-01-16
 | | doubledrooks: <David2009>: I didn't examine 35...Bd6 either, but after playing the position against the computer several times and making an assortment of blunders I finally won by swapping down. |
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Dec-01-16
| | wtpy: This puzzle would have been a weekender if started a move earlier. Starting with Rf7 it was pretty easy for Thursday. |
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Kibitzing
sac: 35.Rxf7