| Feb-10-13 | | SBB: Tough one. I actually did see Bxf3, but was skeptical because I didn't see the continuation after 31. Kf2. |
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Feb-10-13
 | | An Englishman: Good Evening: Ran into the same problem as <SBB>. Of course, in a real game, I never would have known there existed a win and would have settled for the attempted trap 29...Qc4; 30.Nxa6,Qxc3; 31.bxc3,Nxa6; 32.Rxa6,Bc4. |
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Feb-10-13
 | | offramp: I would've played...Bxf3 faster than one of my own lightning heartbeats. |
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| Feb-10-13 | | dannymay: After 38...Qd5, what's the coup de grace? |
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Feb-10-13
 | | Once: BPCF = British Postal Chess Federation.
And I think that is what makes this puzzle insane, at least for us. Under normal time controls it would be hard to figure out all the variations in this POTD. Sure, we can work out the first few moves, but seeing enough to be certain of the sacrifice would need an amount of time more suited to ... correspondence chess. Funny that yesterday's POTD was easier for us than the OTB players because it was a puzzle. But today's POTD is arguably harder for us because we are treating it as a puzzle rather than correspondence chess. |
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| Feb-10-13 | | morfishine: Black: No reasonable checks, only a few captures, so lets go straight to 29...Bxf3 (1) <29...Bxf3> Clears the d-file for the rook, assaults the White King side & opens a potentially useful square for the Knight: d5 <30.Rxf3 Rd1+> White faces a tough decision: 31.Rf1 or 31.Kf2; I'll have to look at both since I have a bad habit of playing weaker moves for the losing side... (1a) <31.Rf1 Rfd8 32.Rxd1 Rxd1+ 33.Kf2 Qf5+ 34.Kg3 Nd5> 
click for larger view
This looks way too strong for Black; Lets check 31.Kf2 (1b) <31.Kf2 Nd5> This nice intermezzo attacking the White Queen keeps the momentum in Black's favor; Tempting is 31...Bh4+ 32.g3 Rf1+ 33.Kxf1 Qxf3+; but the attack runs out of steam after 34.Kg1 Rd8 35.Bd4 Qd1+ 36.Kf2 <32.Bd4> Probably best since I can't find a decent square for the White Queen; Per move 31, Black still threatens the simple combination Bh4+/g3 Rf1+/Kxf1 Qxf3+, which is now stronger having interpolated 31...Nd5; <32...Nxc3 33.bxc3> Probably best, keeping the d-file closed <33...Rfd8> Threatening exchanges on d4 winning the Knight on c5 
click for larger view
Best here looks like 34.Ra5; but after 34...R8xd4 35.cxd4 Rxd4 36.Nxd4 Qxd4+ 37.Ke2 Bxc5
Black is winning
**********
PM: Interesting, White tried to keep his Queen on with 32.Qc2; Guess it really didn't matter |
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| Feb-10-13 | | morfishine: <dannymay> On your Question <After 38...Qd5, what's the coup de grace?> The primary threat is 39...Qxe5+; If 39.Nd3, then 39...Rc8+ 40.Kd2 Rc2+
and if 40.Kb4, then 40...Qb5 mate
If White runs right away with 39.Kb4, then 39...Rb8+ 40.Ka4 Qc6+ 41.Ka5 Bd8 mate White is in virtual zugzwang |
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| Feb-10-13 | | gofer: Well, with the bits on the board and playing around with
this one (because its "Sunday"). It becomes clear that
although the following is obvious after only a few seconds... <29 ... Bxf3>
<30 Rxf3 Rd1+>
<31 Rf1 ...>
The follow up move that seals the deal is less obvious. I tried...
31 ... Rfd8?
31 ... Bh4?
31 ... Bxc5?
31 ... Rxf1+ 32 Kxf1 Qd1+ 33 Qe1 Qxe1+ 34 Kxe1 Nc2+ ?
31 ... Rxf1+ 32 Kxf1 Nd5?
Finally, I realised that with Rd1 still on the board
31 ... Nd5 was really quite nice!!!
<31 ... Nd5>
click for larger viewWhat is white to do? Black threatens Qc3 and Be3 and white is going to struggle to protect both! 32 Ra4 Rxf1+
33 Kxf1 Qf5+
34 Rf4 Nxf4 
~~~
So white didn't like retreating the rook, which is understandable
given the mess this creates, so I should have found 31 Kf2,
but didn't.
Truly "insane"... ...but not for the first two moves... |
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| Feb-10-13 | | JimNorCal: 33. ... Rf1 is really nice.
At the end black is only up a pawn and threatening to win a second. Very entertaining! |
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| Feb-10-13 | | mistreaver: Sunday. Black to play. Insane. 29...?
Ahhh, typical sunday mess is at the board. Everything is hanging but there sure
is some brilliant blow.
29... Bxf3
(The most obvious move, made on the basis that it is puzzle position, over the board i would surely play
Qc4. Text move cleares the d- file, and if there is any winning attempt i guess
it should be it (unless there is some ultra subtle move with the knight)).
30 Rxf3 Rd1+
31 Kf2 (more or less forced)
31... Bh4+
32 g3 (32 Ke2 Qxg2 is i think enough compensation)
32... Qh3 and black has very strong threats.
I have by no means exhausted every possible continuation but i will put a stop here since the position is too complicated
and i don't like the fact that knight on b4, that is apparently excelently placed made no move.
Time to check.
---
Yeah, as i suspected, i totally mised Nd5 and Rf1. My line with Qh3 is dynamic balance after Ke2 Nd5 sequence. I am in no mood for analysis today and am probably going to lose many rating points on ICC after this. zero for today, 5.5/7 for this week. |
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| Feb-10-13 | | Patriot: Black is up the bishop pair. White threatens 30.fxg4. The only candidates are 29...Bxf3 and 29...Qc4.
29...Bxf3 (threatening mate on the move) 30.Rxf3 Rd1+ 31.Rf1 Rfd8 32.Rxd1 Rxd1+ 33.Kf2 Qf5+ 34.Kg3 and the white king looks very exposed. (34.Ke2 Qf1#) I think white will have to interpose something since black's threat is 32...Qe2. There is much more to this so I'm not sure if this works. For instance, 32.Bd2 or 32.Nd2 or 32.Bd4 or 32.Nd4 are options. |
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| Feb-10-13 | | Patriot: 31...Rfd8 is too slow, which can be met by 32.Ra1. I missed the purpose in 31...Nd5 other than hitting the queen. I don't see how anyone can calculate all of this OTB. Maybe they didn't. |
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| Feb-10-13 | | gambler: @SBB:
To me, 29. ...Bxf3 30. Rxf3 Rd1+ 31. Kf2 was the critical line. The others are fairly quickly calculated...So I dug deep here. To be honest I could not see a clear win, but my gut fealing told me, that after 31. ...Qh4+ 32. Rg3 Qxh2 Black should have enough compensation for the bishop.
If 31. ...Qh4+ 32. Ke2 is chosen we play 32. ..Nd5 after which either 33. Qa5 Nxe3 should win the h-pawn, or 33. Kxe1 Nxc3 34. bxc3 the queen for a rook and a knight. I am not 100% sure of these lines. However, my gut feeling tells me, that with these calculations and the evaluation of the position, there should be some advantage or at least some perpetual. As seen in the game, Qh4+ was not the best move... I also looked at 31. ...Nd5 (like in the game) but could not find a winning continuation after 32. Qc2.
However, The Qh4+ idea gave me confidence that 29. ...Bxf3 is the right move to play and as the game progresses, it is easier to see the winning combinations, so maybe I could have calculated 31. ... Nd5 when the game was at this point. Still 31. ... Qh4+ is a strong move, so defenitely no miscalculation here. |
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| Feb-10-13 | | James D Flynn: 29……Bxf3 30.Rxf3 Rd1+ 31.Kf2(not Rf1 Nd5(the White Q has no squares that protect the B on e3 if she flees to a5 then Nxe3 threatens mate by either Qxg2# or Rxf1# therefore White must try attacking the Black Q) 32.Ra4(if h3 the same reply wins the Q) Qe2 33.Rxd1(amusing is Q 33,Qc4 hoping to get a R for the Q ) Nxe3 and White can choose how he wants to be mated) Qxd1+ 34.Kf2 Nxc3 and Black has won a Q for 2 Ns the expose K leaves White with a hopeless position) Nd5 32,Qa5(the e3 B is protected by the R and K) Bh4+ 33.Ke2(if g3 Rf1+ 34.Kxf1 Qxf3+ 35.Bf2 Ne3+ 36,Ke1 Qd1# )Qxg2+ 34 Kxd1 Qxf3+ and Black now wins the B on e3 leaving pieces temporarily even but t he White K is hoplessly exposed e.g. 35, Kc1 Nxe3(threat Qd1#) 36.Qd2 Qh1+ 37.Qd1 Qxd1# |
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Feb-10-13
 | | agb2002: Black has the bishop pair for a bishop and a knight. White threatens 30.fxg4, the knight and the a-pawn.
The first idea that comes to mind is 29... Bxf3, clearing the d-file for the rook and d5 for the knight: A) 30.Rxf3 Rd1+
A.1) 31.Rf1 Nd5 followed by Nxe3, recovering the piece and keeping the attack and the pawn. A.2) 31.Kf2 Bh4+ 32.g3 (32.Ke2 Re1+ 33.Kd2 (33.Qxe1 Bxe1 34.Kxe1 Nc2+) 33... Qxg2+ looks bad for White) 32... Nd5 A.2.a) 33.Qa5 Rf1+ 34.Kxf1 Qxf3+ 35.Ke1 (35.Bf2 Ne3+ and mate next) 35... Nxe3 36.gxh4 Qd1+ 37.Kf2 Ng4+ and the white king seems lost in a mating net. A.2.b) 33.Qc2 Rf1+ 34.Kxf1 Qxf3+ 35.Ke1 (35.Bf2 Ne3+ and 36... Nxc2; 35.Kg1 Nxe3 36.Qf2 Qd1+ etc.) 35... Nxe3 36.Qe2 Qh1+ 37.Kd2 (37.Kf2 Ng4#) 37... Bg5 looks crushing. B) 30.g3 Qh3 31.Rxf3 (31.Rf2 Rd1+) 31... Rd1+ and mate soon. |
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| Feb-10-13 | | patzer2: Penrose's 29...Bxf3!! is a magnificient demolition and clerance move, which pries open the White position for a decisive attack on the exposed King and several loose pieces. The move accomplishes at least four positional objectives: 1. It clears the d-file for the coming Rook check.
2. It clears the d-5 square for a key follow-up Knight fork. 3. It decoys the White Rook off the back rank (i.e. 30. Rxf3 is forced). 4. It demolishes just enough pawn structure to open up a diagonal for a key follow-up Bishop check (i.e. 32...Bh4+  ). I put it in my clearance collection, since it seems to emphasize this tactical theme. However, the demolition of pawn structure, Knight Fork, decoy and deflection (i.e. removing the guard) tactical themes all play an essentiale role in the follow-up to this combination. Typically, the demolition combinations involve multiple tactical themes. So I've also added it to one of my demolition of pawn structure collections. |
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| Feb-10-13 | | Tiggler: 31... Nd5 was the ! move here. Obvious up to there, but I missed this GOOT move. |
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| Feb-10-13 | | Tiggler: Don't feel bad if you missed this one. Penrose was a genius from a family of genii. |
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| Feb-10-13 | | M.Hassan: "Insane"
Black to play 29...?
Equal
Removal of Bishop from the d file with a subsequent check by Rook seems very obvious: 29...........Bxf3
30.Rxf3 Re1+
31.Rf1 Nd5!
32.Qd4
<if 32.Qc2 Rxf1+ 33.Kxf1 Nxd3+ with a Royal fork> 32...........Rxd4
33.Bxd4 Nf4
34.Rxf4 Qxf4
Black is much stronger in materials and should win |
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| Feb-11-13 | | Abdel Irada: <<•>Caissa's Impressionist?<•>> I am come lately to this problem (the old schedule conflict strikes again), but I offer a few impressions. "Take my bishop ... please!"
Oh, wait. That's a Henny Youngman impression. Not the kind I had in mind. <<•> 29. ...Bxf3! > This key move cries out to be played. Black's precariously placed pieces don't allow for quiet retreats of the queen, which is now under attack, so in the spirit of the puzzle, no other move would do. <<•> 30. Rxf3, Rd1†31. Kf2 ... >
Quickly ruled out is the interposition: 31. Rf1?, Nd5! . White has no good square for the queen, and counterattacking Black's will only drive it to the more threatening square e2. This is indefensible. <<•> 31. ... Nd5 > And here I am going to stop. I feel morally certain that Black's position more than compensates for his material deficit, but moral certainty and proof are very different things, and meanwhile, this is no longer the puzzle of the day. |
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Kibitzing
sac: 29...Bxf3