< Earlier Kibitzing · PAGE 3 OF 3 ·
|Aug-19-07|| ||Creg: <znprdx> I shouldn't be surprised if this was book, or prepared beyond the point of the exchange sac. Now-a-days memorizing lines are vital for survival at this level. |
However, I along with many others here do not have this line memorized. Many found the key moves, and I too saw the idea, thus proving that without study or memorized lines one can devise a winning plan.
Memorizing a single line only helps when that line is played, but understanding the thematic requirements of the position will help you no matter what line you or your opponent play.
|Aug-19-07|| ||playground player: Great game, enlightening analysis by <Capablanca Fan>... but a "puzzle"? Did someone really expect one of us to find all 29 moves for both sides? That's two-thirds of the game!|
|Aug-19-07|| ||elhares: good puzzle not very hard to see 13.h6g5 followed with N take d5 and then Qa5 with good chances for black infact befor move 13 black sitaution was bad but zuszsa polgar managed to find that attack which converted the game good puzzle lets say 1900 rated player puzzle.|
|Aug-19-07|| ||sharkw: <Zzyw> I would say after 13...Nxd5 White certainly has better than 14. exd5, namely 14. Bxd8 and I don't think Black has a good continuation with the queen sacrifice.|
|Aug-19-07|| ||patzer2: For today's very difficult Sunday puzzle solution, Susan Polgar sacrifices the exchange with 13...hxg5!! in order to whip up a decisive attack on White's helpless, uncastled King position. |
With the White Queen out of play, and three active pieces focused on White's uncastled King, after only a few moves, Susan's sacrifice is sound (even if one does not immediately see the combination all the way through to the game's end).
|Aug-19-07|| ||Fezzik: My favorite move was 13...g6!! 14.Nf6#.|
|Aug-19-07|| ||Quad Fifties: 13...g6??|
|Aug-19-07|| ||fm avari viraf: Black seems to be tied up & if White gets a chance to castle King-side, the King would be safe & sound. Hence, 13...hxg5 exchange sacrifice is a good speculative alternative. After 14.Qxh8 Nxd5 15.exd5 Qa5+ 16.Kd1 [ not 16.Kf1 then ...Qd2 ] ...Bg4+ 17.f3 [ not 16.Kc1 Rc8+ wins ] 17...Nxf3 18.gxf3 Bxf3+ till here, I could visualise but there are many good & bad alternatives & a long battle still to be fought!|
|Aug-19-07|| ||sfm: Great game! What a mess!|
|Aug-19-07|| ||al wazir: <MAJ>: I deleted the post you responded to after seeing that 16. Kf1 is answered by 16...Qd2. Then I restored it when I noticed 17. Qh5. But if 17...Qxd3+ (17...g4 18. Bc4), then 18. Ke1 (18. Kg1 Ne2+ 19. Kf1 Ng3+, etc.) g4 (18...Bxd5 19. Qe1), and I see I'm beating a dead horse.|
|Aug-19-07|| ||kevin86: What a move! Zsuzsa-AKA "Ginger Snap" played a brilliant move on move 14 and the fur flew!|
A real fun game to watch!
|Aug-19-07|| ||Richard03: Black annotated this game in 46ChessInformant207. Black placed question marks after her 20th and 21st moves. With that in mind, is further effort needed?|
|Aug-19-07|| ||Some call me Tim: <psmith> If 23...g6 24. Qh7 and both mate and Qxg6 are threatened which seems to give White a far more deadly attack and also drop two pawns (g6 and g5). 24...f5 is clearly poor in this line as 25. Qxg6+ just cleans up. I think Polgar preferred a perpetual to this and she also saw that White could overestimate his chances by avoiding the perpetual.|
I agree this does not seem to be a problem that leads to a forced win, or even to a winning advantage with precise play (unless I am missing something). I saw 13...hxg5 and the follow up quickly but did not (and could not!) calculate all of its possibilities. It just made Black's game so much more fun to play it was irresistible. I did not see to play 14...Nxd5 to prevent b4 after Qa5+, as I felt Qxa3 was enough to win. Polgar's idea was far more accurate, also taking the N from its strong d5 position. Great thought provoker!!
|Aug-19-07|| ||TheaN: I guess it's a 6.33/7 for me this week, for those that are in a good mood might give me a third more. Not a bad score for me, at least.|
Lets not talk about the first move. 13....♙xg5 14.♕xh8 is just what happens and seems to be Black's best shot. White position is horrible when unable to castle. Got the points there.
Now I tripped over the ♘ on d5. I took it with the ♗ first to take in a more flexible piece. Looks like I went wrong there: 14....♗xd5 15.♙xd5 ♕a5+ and White is pretty much free to play 16.♔d1 without too much danger. 16.♔f1 is met by ♕d2. Although I did see ♕d2 I wasn't confinced, not even with the ♗ on e6 instead of the ♘ on e7. Only now I notice that not only d3 but also e2 and b2 are under attack after that move and White is very bad there.
I also noticed that 16....♗g4+ in the main line would win. I'm not going indepth there, just because I didn't. I got stuck too much on 14....♗xd5 and 16.♔f1 that I did not really calculate the main line, but at least that seemed to win with the c-file for Black, etc.
I got the idea of the puzzle, and OTB I might have seen the right combination if I'd actually played it, but here, I didn't. I still guess that Black is savable after 13....♙xg5 14.♕xh8 ♗xd5 15.♙xd5 ♕a5+ 16.♔d1 ♘xd5, but that is not winning. On to next week, on to 7/7.
|Aug-19-07|| ||Some call me Tim: <Richard03> After reading your comment I went back and looked at move 20 and have had plenty of fun with 20...Bxd5. I am sure I have only scratched the surface but a couple possibilities are 21. Kb3 axb5 22. Bxd5 Qa4++. Or 21. Rhd1 Bxc4 and everything I have tried results in a winning attack for Black. Give it a whirl and see whether this is better than 20...Bxh1.|
|Aug-19-07|| ||Some call me Tim: Correction, on the last one I meant 22...Qa4#, not ++.|
|Aug-20-07|| ||MostlyAverageJoe: <openingspecialist: I think that this is maybe a poor problem>|
<znprdx: absolutely agree <openingspecialist>>
I disagree with the comments suggesting that this was not a good puzzle, because white could have drawn. The draw was only possible because of two mistakes by the black: 20...Bxh1 and 23...f6.
Otherwise, the line played by Zsuzsa up to move 20 was absolutely winning, but should've been followed by 20. ... Qa4+ (see my previous posting for details). Note that 20...Bxd5 suggested by <Some call me Tim> is mostly defused with 21.Qh3 (attacking R on c8)
<Creg> had a good comment, worth repeating: <Once the white king is exposed and you can see that your remaining pieces can begin entering into the attack quickly you should realize that your opponent is simply under pressure and that you hold a strong initiative.> This is completely in agreement with Qa4+ continuing the attack instead of Bxa1?, prematurely cashing in the exchange.
<Some call me Tim: <psmith> If 23...g6 24. Qh7 and both mate and Qxg6 are threatened> Mate threat is easily handled with 24...Qb7. Qxg6 is not a threat there, since the pawn on f7 protects g6. My Hiarcs agrees with <psmith>'s Fritz in that 23...g6 is the best move (although it disagrees on f5 followup). These "ideas" displayed by Fritz quite frequently make no sense and are not reflected in the proposed lines...
|Aug-20-07|| ||zanshin: <openingspecialist: I think that this is maybe a poor problem> <znprdx: absolutely agree>|
Unfortunately, I agree. I know that we should use our brains and not engines, but in this case, I can't help but present some Fritz analysis. The top two moves were 13...Bxd5 and 13...hxg5. The practical and boring Bxd5 gives black the advantage, the bold and sensational hxg5 evaluates as equal. As a basketball analogy, a coach would chew out a player who goes for a risky (but crowd-pleasing) behind the back blind pass when a simple bounce pass would suffice. So which move represents the "solution" to the puzzle?
1. (-0.77): 13...Bxd5 14.exd5 hxg5 15.Qxh8 Qa5+ 16.Kd1 Qa4+ 17.Kc1 e4 18.Qh3 exd3 19.Qxd3 Nxd5 20.Qe4+ Ne7 21.Re1 axb5 22.Kb1
2. = (-0.23): 13...hxg5 14.Qxh8 Bxd5 15.0-0 Be6 16.bxa6 Ng6 17.Qh7 Nf4 18.Bc4 Rxb2
|Aug-20-07|| ||MostlyAverageJoe: <zanshin: <openingspecialist: I think that this is maybe a poor problem> <znprdx: absolutely agree> Unfortunately, I agree. I know that we should use our brains and not engines, but in this case, I can't help but present some Fritz analysis.>|
May I suggest that you turn on the "Deep analysis" mode in Fritz and let it crank for a while, pondering what to play as 13...?
Seeing that the <13...hxg5 14.Qxh8 Bxd5> line you're quoting from Fritz takes a suboptimal turn on the third ply (Bxd5), I cannot help but think that you just did not let it run long enough.
|Aug-20-07|| ||zanshin: <MAJ> I let Fritz run for about 30 mins to 17-ply. Admittedly, that's not a very deep analysis. I was confident the evals had stabilized, but I'll let Fritz run longer and will post an immediate retraction should they change.|
|Aug-20-07|| ||MostlyAverageJoe: <zanshin> This is surprising. 17 plies should've been good enough. Maybe my recollection that software rates 13...hxg5 as a top-rated move is faulty; I'll re-do the analysis later tonight.|
Letting the engine run on the initial position is usually not the best thing to do in complex situations. One has to do some sliding analysis - pick a line, run it forward, then move back one ply at a time, while letting the program re-analyze it, and back-track to the initial position. This should be done in the "infinite analysis" mode, and typically identifies mistakes made by the software in selecting best moves at the deep levels of analysis. Big enough hash memory allocation is of utmost importance here; it enables the engine to retain valuations of deep moves while sliding back. It may take several iterations to get the real results.
The deep analysis mode for Fritz is supposed to do automatically something like what I described above. With other engines, this may need to be done manually.
|Aug-20-07|| ||zanshin: <MostlyAverageJoe: <zanshin> This is surprising. 17 plies should've been good enough. Maybe my recollection that software rates 13...hxg5 as a top-rated move is faulty; I'll re-do the analysis later tonight.>|
<MAJ> Don't bother. You were right. Another 10 minutes and 1 ply deeper in Infinite Analysis mode, and 13...hxg5 comes out on top. I guess it *is* a good puzzle then ;-) I have even more admiration for Susan.
1. (-1.78): 13...hxg5 14.Qxh8 Nxd5 15.0-0 Nf4 16.Rad1 Nxd3 17.Rxd3 axb5 18.Rd2 Qf6 19.Nc2 Qf4 20.Rxd4 exd4
2. (-1.02): 13...Bxd5
3. (0.33): 13...axb5 14.0-0 Qd7 15.Be3 Nxd5 16.exd5 Bg4 17.Qh4 Ne2+ 18.Bxe2 Bxe2 19.Rfc1 Be7 20.Qg3 Qg4 21.Qxg4
|Aug-20-07|| ||MostlyAverageJoe: <zanshin> Thanks for reporting the deeper analysis results!|
My recollection is that with sliding forward/backward, the valuation at move 13 goes all the way to -5 or better. Here's the interesting part:
On the sliding forward analysis, the moves 13-20 appear to be pretty much best for both sides. However, a really deep and complete analysis starting at 20 ...? results in valuation -9 or so. Now one could ask: if moves 13-20 are optimal, then how come the valuation at move 13 is only -5?
The reason is that engines do a lot of search space pruning. For example, if two alternatives evaluate at (-2) and (-5) (with relatively shallow analysis), the one evaluating at (-5) will be abandoned. The only way to revisit it is to do a deep analysis on the (-2) branch and, for example, prove that it really is (-6).
Once the position at move 20 evaluates to (-9), sliding back analysis uncovers a lot of (shallowly analyzed) branches that appear to evaluate at (-5) or so. Descending into those branches would be very time-consuming (so I did not bother). Furthermore, the limited memory for hash (where the engine stores valuation of examined positions to avoid repeating the searches) causes the engine to discard the least-used portion of that hash, so that sliding back forces it to re-examine the discarded lines (hence the time-consuming behavior).
Oh, well. The bottom line is that engine is still only a tool, and needs careful guidance. I found that sliding forward/backward produces results much faster than just letting the engine run, but selection of when to stop analysis at any particular move is tricky.
This is why it rather annoys me when people disparage computer-aided analysis as requiring no human thought - there is still a fair amount of brain effort needed there, at least in positions that do not result in an immediate mate (where immediate is about 15 or fewer moves).
|Aug-20-07|| ||zanshin: <MAJ> Thanks for the explanation on sliding forward / backward. When the temporary forums open on the GMT game, I'd like to get back to you on this topic ... probably later in your forum so I won't forget and so I don't flood this forum with off-topic posts!|
|Aug-26-07|| ||Zzyw: <sharkw>, you're right. My previous comment was complete bullocks.|
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