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Later Kibitzing> |
| Aug-30-08 | | lost in space: My line is looking like this:
35...Rxf3 36. Qxf3
or 36. Kxf3 Qf4+ 37. Kg2 Qg3+ 38. Kf1 Rf7+ 
or 36. Rxh4 Qxh4 37. Kxf3 (37. Qxf3 Qh2+ 38. Kf1 Rf7 39. Qxf7 Kxf7 40. Rxc5 Qxb2 41. Rxc6 Qxb1+ ) 37...Rf7 38. Kg2 Rf4 39. Rg1 Rxg4+ 40. Qxg4 Qxg4 41. Kh2 Qf4+ 36...Qd2+ 37. Kf1 Qxb2 38. Rxc5 Qxb1 39. Kg2 Qb2+ 40. Kf1 Rf7 (not!! 40..Nd4 41. Rc8 and it is white which will loose this game!!) 41. Qxf7 Kxf7 42. Rxh4 Nd4 
click for larger view |
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| Aug-30-08 | | TiTi: White can't play 38. Qxf2? |
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Aug-30-08
 | | Once: 38. Qxf2? Rxh1+ 39. Kxh1 Qxf2 or 39. Kg2 Rh2+ 40. Kxh2 Qxf2+ |
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| Aug-30-08 | | zb2cr: Rats. Saw the first move, but missed the all-important follow-up 36. ... Qd2+. I thought Black had time for 36. ... Nd4 first. That turns out not to work. |
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| Aug-30-08 | | perhaps: TiTi: White can't play 38. Qxf2?
yes, but looses the queen or worst: 38...Nh1+ 39Kg2 Nh2+ 40Kxh2 Qxf2+
or 40Kg3 or g1 Qxf2++ |
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| Aug-30-08 | | johnlspouge: Saturday (Very Difficult): Black to play and win.
Material: N for B. The White Kg2 has 4 legal moves, but 2 of them are on the h-file where Black has a battery Rh7 and Qh6 behind Bh5, which can discover attack on Rh1. The Black Rf4 exerts pressure on the backward Pf3, and discovers the entry point d2 for Qh6. Given the control of dark squares around Kg2 exerted by Bh5, 35…Rxf3 and 36…Qd2 are promising candidates already. The Black Nc6 is the only passive Black piece. Candidates (35…): Rxf3, Qd2
35…Rxf3
White must recapture or passively accept a major breach in his defenses without compensation. (1) 36.Kxf3 Qf4+ 37.Kg2 Qg3+ 38.Kf1 Rf7+ 39.Qf2 Qxf2# (2) 36.Qxf3 Qd2+
White cannot feasibly interpose, so Kg2 has 3 flight squares. (2.1) 37.Kh3 Be1#
(2.2) 37.Kg1 Qxb2 (threatening 38.Qxc1+ and 38.Nd4)
Activation of passive pieces is the hallmark of a good candidate. Without further calculation, the threat of activating Nc6 strongly confirms the candidate 35…Rxf3. The Nc6 now threatens the light squares around Kg2, to complement dark square control from Bh4. Counterattack is infeasible, and so White can defend Rc1 (with Qf3 only) or move Rc1 to safety (only along the 1-st rank, to maintain protection of Bb1). Sacrifice of an exchange is now an infeasible defense, because it leaves White a P down defending a huge attack. 38.Qf1 Nd4 (threatening 39…Nd2+, etc.)
White has to sacrifice at least an exchange to survive. The other variations from 37.Kg1 resemble variations from 38.Kf1, next. (2.3) 37.Kf1 Qxb2 (threatening 38.Qxc1+ and 38.Nd4)
(2.3.1) 38.Qd1 Qf2#
(2.3.2) 38.Rd1 Nd4 39.Qe3 [Qg2 is fatal] Bf2 (threatening 40.Bxe3 and 40.Rxh1+) 40.Qxf2 Rxh1+ 41.Kg2 Rh2+ 42.Kxh2 Qxf2
Black has Q+N+P for R+B.
I preferred 37...Qxb2 to 37...Bf2, to reclaim material and let Nc6 enter the attack, so the computer analysis will be interesting (mainly to see how much more efficient Chigorin's 37...Bf2 was :) |
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| Aug-30-08 | | johnlspouge: Here is the usual Mom-and-Pop evaluation by Toga II 1.3.1 with <the last move entered> emphasized. and my summary at the end. (Humans can improve near the end of the full computer variation.) There is a big surprise for everyone :)
(1) 35...Rxf3 36.Qxf3 Qd2+ 37.Kg1 <Bf2> 
click for larger view [ply 15/55 time 00:25 value (to White) -9.33]
38.Kf1 Nd4 39.Bxd4 Qxc1+ 40.Ke2 Rxh1 41.Bxf2 Qd1+ 42.Ke3 Qxb1 43.Qxh1 Qxh1 44.Kd2 Qb1 45.Bxc5 Qb2+ 46.Kd1 Qxb3+ 47.Kd2 Qb2+ 48.Kd1 Qc3 49.Bb4 Qxd3+ 50.Kc1 Qxe4 51.Bc3 (2) 35...Rxf3 36.Qxf3 Qd2+ 37.Kg1 <Nd4> 
click for larger view [ply 15/69 time 00:56 value (to White) -9.04]
38.Bxd4 Bf2+ 39.Kf1 Qxc1+ 40.Ke2 Rxh1 41.Bxf2 Qd1+ 42.Ke3 Qxb1 43.Qxh1 Qxh1 44.Ke2 Qc1 45.b4 Qb2+ 46.Kf3 Qxa3 47.Bxc5 Qxd3+ 48.Be3 Qf1+ 49.Kg3 Qe1+ 50.Kf3 Qxb4 51.Bf2 a5 52.Be3 (3) 35...Rxf3 36.Qxf3 Qd2+ 37.Kg1 <Qxb2> 
click for larger view [ply 18/57 time 01:34 value (to White) +0.54]
38.Rf1 Qd4+ 39.Kg2 Qd8 40.Qe3 Nd4 41.b4 Bg5 42.Qf2 Bh4 43.Qd2 Bg5 44.Qc3 Rxh1 45.Rxh1 cxb4 46.axb4 Qf8 47.Rf1 Bf4 48.Ba2 Chigorin's 37...<Bf2> appears best and slightly better than 37...<Nd4>. Everyone went for 37...<Qxb2> to justify the initial sacrifice 35...Rxf3, but it draws at best and even permits White some pull after 38.Rf1. <dzechiel>, you were right to be cautious about 37...<Qxb2> ;>) |
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| Aug-30-08 | | johnlspouge: An additional note: after 37.Kf1, best play follows <lost in space>'s variation closely. |
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Aug-30-08
 | | chrisowen: That game is quite daring, h3 and black achieves d5. Rxf3 is is the real stunner, I bet this took time for Isidor to comprehend it. |
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Aug-30-08
 | | kevin86: The opening puzzle position looks like a paradox:black is attacking,but the rook pin seems to be stalling the thrust. Chigorin pulls a flanking manoever the leave white in a box. White seems afterward to have one less defender than he needs-and his position collapses in a chain reaction. |
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| Aug-30-08 | | Jack Kerouac: Combinations cumputers do not allow anymore.
Or do they....? |
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| Aug-30-08 | | Marmot PFL: Found the right idea but could not make it work. Missed 37...Bf2+!, unfortunately after 37...Qxb2 38.Rf1 its black that's in trouble. |
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Aug-30-08
 | | Jimfromprovidence: After 3…Rf3, I tried 36 Rxh4 Qxh4 37 Kxf3 as a potential holding defense for white.
click for larger view Instead, I found a puzzle within the puzzle. The challenge is to find black’s best move to play and win. |
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| Aug-30-08 | | johnlspouge: <<Jimfromprovidence> wrote: After 3…Rf3, I tried 36 Rxh4 Qxh4 37 Kxf3 as a potential holding defense for white.
Instead, I found a puzzle within the puzzle. The challenge is to find black’s best move to play and win.> Yes, it is definitely not what you would expect. Thanks. |
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Aug-30-08
| | Once: <JimfromProvidence> I am not sure about black's best move in your position, but there seem to be several ways to win. 37. ... Qh3+ 38. Kf2 Rf7+ 39 Ke1 Qg3+ 40 Kd1 Rf2
or ...
37. ... Qh6 38. Qg2 Qf4+
37. ... Qg5 and 37. ... Rf7+ also look strong.
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| Aug-30-08 | | johnlspouge: Hi, <Once>. Most atypically, you speak in variations here ;>) Most of us would go for 37...Qh3+, but the computer declares 37...Qh6 much more powerful. (Both win easily.) I find it interesting that in chess (as in life), delay of gratification is powerful, but judgment about when to delay so hard to acquire. More than before, I am attuned to a mate-in-one threat as sometimes preferable to check, but <JfP>'s problem is more subtle yet: here, restriction of the K's flight is preferable to check. |
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| Aug-30-08 | | 456: Friday puzzle Aug-29-08 <16. ?> Alekhine vs Van Mindeno, 1933 |
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Aug-30-08
| | Once: <johnlspouge> I can speak bureaucrat and geek too, when the occasion calls for it! I normally leave the variations to those much better qualified than me. 37. ... Qh6 is indeed a fascinating counter-intuitive move. It doesn't threaten anything and it seems to be moving backwards. But it sets up double threats along the h file and the f4 square. White can't defend both. Talking of delayed gratification, the black knight has sat on c6 since move 24, but Chigorin quite rightly doesn't play the "obvious" Nd4. The idea of a knight outpost sits as an unrealised threat for the rest of the game. |
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| Aug-30-08 | | brainof7: 35... Rxf3 36. Qxf3 Qd2+
and i have a really hard time beating a computer from that position but it is definately winning. |
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| Aug-30-08 | | BlackWaive: Saturday.
After a few minutes, I found 35...♖xg4+ 36. fxg4 ♕f4. I believe that White loses quickly in this line if not for the saving move, 37. ♖h3, which I missed. According to Toga II 1.4β5c, after 35...♖xg4+ 36. fxg4 ♕f4 37. ♖h3 the position is drawn (with an evaluation of +0.14) with best play from both sides. |
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Aug-30-08
| | Jimfromprovidence: <<After 34…Rf3, I tried 35 Rxh4 Qxh4 36 Kxf3 as a potential defense for white.
click for larger view Now, here’s a puzzle within the puzzle. The challenge is to find black’s best move to play and win.>> As <johnlspouge> and <once> have stated, 37…Qh6 wins more material than the simpler 37…Qh3 +. Some variations include the following : To try to guard the h file. If 38 Qg2, then 38… Nd4+! 39 Bxd4 Qxc1 40 Bxe5 (unforced but representative) Qd1+ 41 Kg3 Qe1+ 42 Qf2 Rh3+ 43 Kxh3 Qxf2, etc. To try to guard the h file version 2. If 38 Kg2, then again, 38…Nd4!. 39 Bxd4 Qh2+ 40 Kf1 Qf4+ 41 Kg1 Qxc1+ 42 Qf1 Rh1+ 43 Kxh1 Qxf1+, etc. To try to trade queens. If 38 Qe3 , then 38…Qh2! 39 Qf2 Rf7+ 40 Ke2 Rxf2+ 41 Ke1 Qg1# (41 Ke3 Qg3#). |
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| Aug-30-08 | | Rama: The f4 square beckoned me, too. 35. ... Rxg4+, 36. fxg4 Qf4, with unstoppable threats, many similar to the game's. I felt the check was more forcing than Rxf3. What am I missing? |
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| Aug-30-08 | | johnlspouge: <<Rama> wrote: The f4 square beckoned me, too. 35. ... Rxg4+, 36. fxg4 Qf4, with unstoppable threats, many similar to the game's. I felt the check was more forcing than Rxf3. What am I missing?> The sequence 35...Rxg4+ 36.fxg4 does not displace Qe2 and permit the critical penetration 36...Qd2+. |
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Aug-31-08
| | Once: <Rama> I went for the same line, but several posts here (and Fritz analysis) show that it does not work. Fritz offers one possible line: 35... Rxg4+ 36. fxg4 Qf4 37. Rh3 (annoyng move!) Nd4 38. Bxd4 Qxc1 39. Bb2 Qxb1
40. Bxe5
click for larger viewThe monster says that this is = 0.00. Material is level and the black attack has been contained. As <Johnlspouge> points out, in the starting position d2 is a sexier square for the queen than f4. |
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| Sep-02-08 | | patzer2: The demolition sacrifice 35...Rxf3!! opens up the White position to a decisive attack. |
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Kibitzing
sac: 35...Rxf3