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Later Kibitzing> |
Aug-31-14
 | | Penguincw: 23.? would make a good mid-week POTD. |
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| Sep-02-14 | | 1d410: <Moszkowski> more explanation needed to convince me |
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Mar-03-16
| | Penguincw: < Aug-31-14 Penguincw: 23.? would make a good mid-week POTD. > I know, right?
As for this actual puzzle, I got 23.Rxd8 Kxd8 24.Nf6. Good enough for me in any puzzles past Tuesday. |
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Mar-03-16
 | | offramp: 24...g4 looks a bit garbage. |
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| Mar-03-16 | | Abdel Irada: <Penguincw: < Aug-31-14 Penguincw: 23.? would make a good mid-week POTD. > I know, right?
As for this actual puzzle, I got 23.Rxd8 Kxd8 24.Nf6. Good enough for me in any puzzles past Tuesday.> That's actually where my calculations left off this time, too. Sometimes a series of moves, although not conclusive in themselves, are so positionally imposing that one simply assumes they will win. Naturally, this doesn't always work, so I don't recommend this procedure in an actual game. There sometimes are unexpected defensive resources that make the "intuitive" sequence unsound. But I would say those are exceptions; mostly, if a position looks strong, it's because it is strong, and so it is in this case. ∞ |
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| Mar-03-16 | | dfcx: black has two extra pawns but its uncastled king lacks protection. White can isolate the king even more with
23.Rxd8+ Kxd8 24.Nf6!
this move limits the kings movements and blocks the black queen and pawn.A. 24...Qf8 25.Qe5 Bd7 26.Rd3 
B. 24....Ke7 25.Qe5 Rd8 26.Qc5+ Rd6 27.Ne4 Qd4
click for larger view
28.Rxf7+ Kxf7 29.Nxd6+ Qxd6 30.Qxd6
C. 24...Bd7 25.Qd2
If black refuses the rook sac with 23.Ke7, white can simply withdraw the rook gaining a piece, and still be able to play Nf6 later |
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| Mar-03-16 | | Jamboree: Can someone explain to me where is the winning line after 24. Nf6 Ke7. Jobava is a 2700 player and didn't play 24. ... Ke7, so there must some obvious flaw in it, but so far, I can't find one. If white goes, for example, 25. Qe2, looking for a deadly diagonal check on b4, then black replies 25. ... b6, stopping any upcoming check with ...c5, which is now protected. If then 26. Ne4 to continue the attack, black's queen gets into the defensive action with 26. ... Qe5, and it looks to me like white's attack has stalled. The game would continue at that point, but white would have to prove all over again from scratch that he has enough of an attack to compensate for the sacced exchange. And if white doesn't do something quickly, black can free his rook with ...Re8 or ...Rd8, after which he is threatening to sac back with ...QxN, RxQ KxR, where the two rooks and extra pawn should survive against the queen. But is there some obvious tactical trick I'm overlooking? It seems to me that Jobava threw the game away with the unnecessary 24. ... g4?, fatally weakening the f4 square and giving the black queen a painful diagonal check from that square. But if he doesn't push the pawn, then f4 remains protected, and instead 24. ... Ke7 gains a tempo while black retains defensive flexibility depending on how white replies. |
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| Mar-03-16 | | agb2002: White has a bishop and a knight for the bishop pair and two pawns. The dark squares around the black king look very weak. This leads to consider 23.Rxd8+ Kxd8 24.Nf6 (24.Qd2+ Kc7, unclear) A) 24... g4 25.Qe5
A.1) 25... gxf3 26.Qd6+ Bd7 27.Qxd7#.
A.2) 25... Ke7 26.Qc5+ Kd8 27.Qd6+ Bd7 28.Qxd7#.
A.3) 25... Qf8 26.Rd3+ Ke7 (26... Bd7 27.Rxd7+ Kc8 28.Qc7#) 27.Nh5 Ke8 (27... f5(6) 28.Qc7+ and mate next) 28.Qf6 and Black looks defenseless against the double threat 29.Rd8# and 29.Ng7+. A.4) 25... Bd7 26.Qd6 Kc8 27.Qxd7+ Kb8 28.Ne8 Rxe8 29.Qxe8+ Kc7 30.Qe7+ Kc8 (30... Kb8 31.Qd8#; 30... Kb6 31.Rb3+ Ka5 32.Qa3(b4)#) 31.Rxf7 wins. B) 24... Qf8 25.Rd3+
B.1) 25... Ke7 26.Qe5 looks similar to A.3.
B.2) 25... Bd7 26.Rxd7+ Kc8 27.Qe5 wins.
B.3) 25... Kc7 26.Qe5+ and mate soon.
C) 24... Bd7 25.Qd2 followed by 26.Qxd7+ with a winning attack. For example, 25... Ke7 26.Qxd7+ Kf8 27.Qd6#. D) 24... Ke7 25.Qe5 looks similar to previous lines.
E) 24... Kc7 25.Qe5+ and mate in two. |
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| Mar-03-16 | | agb2002: The text 25.Qd2+ is much easier and quicker than my 25.Qe5. |
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| Mar-03-16 | | morfishine: <23.Rxd8+> an only mover |
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| Mar-03-16 | | Jamboree: Ah, while I was typing my comment, "dfcx" posted some engine analysis moments before my comment appeared, which may have pre-emptively answered my question. If 24. ... Ke7, white instead plays 25. Qe5!, which is hard to counter. The line given by dfcx fails for black, as does 25. ... Bd7 26. Qc5+ Kd8 27. Qd6. The line 25. ... b6 also fails to 26. Qc7+ Kf8 27. Qxc6 and everything falls apart. The desperado attempt 25. ... Re8 is crushed by 26. Qc5+ Kd8 27. Rd3+ with mate to follow. I can't see any viable defensive resources after 24. ... Ke7 25. Qe5!, so I guess I just answered my own question! |
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| Mar-03-16 | | stacase: A Rook for a Bishop and a tremendous gain in position. After the Rook sacrifice White could hardly do anything wrong. |
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| Mar-03-16 | | gofer: The first move forces the black king into the open and makes sure that
he stays there. The second move keeps the queen out of the picture and
threatens mate in three.
<23 Rxd8+ Kxd8>
<24 Nf6 ...>
click for larger viewWhite has a huge threat and there doesn't seem to be any way for black to
counteract it!
26 Qd6+ Bd7
27 Qxd7#
Black has lost control of d7, e8 and ALL the black squares around its king. So what is black's best defence?
24 ... Kc7
25 Qe5+ Kb6
26 Rb3#
24 ... Ke7
25 Qe5 Rd8
26 Qc5+ Rd6
27 Ne4 Qd4
28 Rxf7+ Kd8
29 Qxd6+ Qxd6
30 Nxd6
24 ... Re8
25 Qd2+ Ke7 (Kc7 Nxe8+ )
26 Qb4+ mating
24 ... Qf8
25 Qe5 Ke7 (Qe7 Rd3+ )
26 Qc5+ Kd8
27 Rd3+
Nope, I can see a defence...
~~~
Err, I didn't see <24 ... g4>, but as it allows Qf4+ I don't see that I should have been expected to... |
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Mar-03-16
 | | Willber G: <Jamboree: Can someone explain to me where is the winning line after 24. Nf6 Ke7. If white goes, for example, 25. Qe2, looking for a deadly diagonal check on b4, then black replies 25. ... b6, stopping any upcoming check with ...c5, which is now protected. If then 26. Ne4 to continue the attack, black's queen gets into the defensive action with 26. ... Qe5, and it looks to me like white's attack has stalled.> This impacted my analysis as well. |
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| Mar-03-16 | | whiteshark: Fail! Didn't find the only winning move <24.Nf6>. :( Instead I calculated <24.Qd2+ Ke7> (24...Ke8 25.Nf6+ Ke7 (...Kf8 26.Qd6#) 26.Qb4+ with #) <25.Qb4+ Ke8 26.Nf6+> with #, completely missing 24...Kc7! which at the end will leave you with an exchange down. <Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better. <>> -- Samuel Beckett |
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| Mar-03-16 | | WorstPlayerEver: If Black had played 21... Qe7 nothing would've happened. |
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| Mar-03-16 | | Oliveira: 24... Ke7 25.Qe5! is beautifully crushing! Black can't make a single helpful move. The sacrifice 23.Rxd8! absolutely took the dark squares away from Black!
click for larger view |
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| Mar-03-16 | | luftforlife: Many thanks to WGM <Natalia_Pogonina> for the link to GM Csaba Balogh's illuminating annotation of this game posted on her website. Best wishes. |
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| Mar-03-16 | | ndg2: I saw the sac on d8, but I couldn't see the strength of Nf6 at first. So I failed with unsuccesful attempts to sac the rook on f7 and then Ne5 instead. But black's king just wanders to the kingside and everything's safe (e.g. after 23. Rf7 Qxf7 24. Ne5 Qf6 25. Qh5+ Kf8, nothing serious happens) |
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| Mar-03-16 | | kevin86: I saw the first move, but not the followup. |
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| Mar-03-16 | | Patriot: It took me about 20 minutes during lunch break to come up with 23.Rxd8+ Kxd8 24.Nf6. Nf6 is a quiet move and was a candidate I chose in response to what would happen on 24.Qd2+ Kc7 25.Qa5+ b6 where 26.Qe5+ is not possible unless the knight interferes with the black queen's defense of e5. |
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| Mar-04-16 | | saturn2: like others i looked both at 24.a Qd2 and at 24.b Nf6, but for a Kc7 seemed a good answer and for b i did not see the decisive attack. so maybe i would have playes 23. Qd2 or Rd3, which would be answered by Be7 or Bc7. so i was rather clueless yesterday. it seems to me black should have played 9..BxN instead of NxN and castled in one of the following moves |
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| Mar-04-16 | | jffun1958:
26. ... Kc8
2-mate
27. Qd6+ Bd7 28. Qxd7#
26. ... e5
3-mate
27. Qxe5+ Kd8 (27. ... Kb6 28. Rb1#) 28. Qd6+ Bd7 29. Qxd7# 26. ... Kb6
3-mate
27. Rb3+ Ka5 28. Qd2+ Ka4 29. Qb4# |
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| Mar-04-16 | | morfishine: <Patriot> Good to see you! As for me, I'm totally spending all my chess time on Chess960 or FischerRandom Regular Chess has become too stale for me and I like the new positions emanating Happy Chess!
***** |
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| Mar-07-16 | | patzer2: Still playing catch up on the puzzles I missed last week. Figured the first move of this Thursday March 3, 2016 puzzle was the sham exchange sacrifice 23. Rxd8+!! However, I didn't see all the decisive mate threats in the variations given below by Deep Fritz 15x64: 23. Rxd8+!! Kxd8 24. Nf6! g4
[24... Bd7 25. Qd3 Kc7 (25... Qxf6 26. Rxf6 ) 26. Qxd7+ Kb6 27. Rb3+ Ka5 28. Qd2+ Ka4 29. Qb4#] 25. Qd2+! Kc7
[25... Bd7 26. Qxd7#; 25... Ke7 26. Qb4+ Kd8 (26... c5 27. Qxc5+ Kd8 28. Qd6+ Bd7 29. Qxd7#) 27. Qd6+ Bd7 28. Qxd7#] 26. Qf4+! 1-0
Black resigns in lieu of 26...Kb6
(26... Kd8 27. Qd6+ Bd7 28. Qxd7#)
27. Rb3+ Kc5
(27... Ka5 28. Qd2+ Ka4 29. Qb4#)
28. Qe5+ Kxc4 29. Qc3#.
Black's decisive mistake appears to be 21...Qg7?, allowing 22. Rf3!  (+2.15 @ 33 depth, Stockfish 5). Earlier, instead of 19...Bc7, which allows 20. Rfd1 =, Black could have held an advantage with 19...h5!  (-0.65 @ 21 depth, Deep Fritz 15). |
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Kibitzing
sac: 23.Rxd8+