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Later Kibitzing> |
| Jan-23-10 | | Halldor: Since this is a puzzle, moving the rook on f8 away is too quiet as a first move, and 30 NxB is also rather dull – not reaching anything. So I found the text move 30 Bxg6 (if BxR?! 31 Bxf7 threatening Ne6 fork). – So I thought 30 Bxg6 Kxg6 31 Nxh3 and White has won a pawn and made the black king more exposed. I didn't get any further and began to check the posts. But when I saw 31...♖a1 mentioned in the posts, I stopped reading and kept on studying the position (I don't regard that as valdid for points since I had peeked, but I had a lot of fun trying out various attacking lines on a chessboard): 
click for larger viewThe next move (because of Black's mate threat) must be 32 Ne6+ KxB 33 Rf3+ and now Black seems to be in deep trouble, 33... Ke8 34 Rf8+ Ke7 35 Qg5+ Rf6 36 QxR# – Or 33... Ke7 34 Qg5+ Ke8 35 Rf8# It seems that Black can't take the bishop, 32... Kh7 33 Qc2+ (mainly to avoid mate) Kh8, and now I don't see anything better than 34 NxQ, hoping for more attacking changes later. |
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| Jan-23-10 | | goodevans: 30 Bxg6 just screams out to be played. That's 6/6 so far this week: All I need is a Sunday that isn't too insane! |
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| Jan-23-10 | | paul1959: <Halldor> In your last line 33 Qc2+ loses to Bd3+ and Black remains a rook up. |
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| Jan-23-10 | | cyclon: A very difficult indeed, but also INTRIGUING. 30.BxG6 Bxf1 [ -Rxg6 31.Rxh3 and White is a pawn up in promising position, -f6 can`t be played because of 32.Rh7+. Whites plan is probably Kh1 and Rg1 or f4. / -Kxg6? 31.RG3 seems already like a winning position / -Qe7 31.BE4 Bxf1 32.RG3 and now -Ra1 33.Ne6++ wins/ -Kh8 33.Nxf7+ wins/ -Kf8 33.NE6+ Rxe6 ( -fxe6 34.Qxh6+ wins) 34.DxE6 (enough time for this, just) -Qf6 (BUT Black DOESN`T have time for -Ra1 because 35.Qh6+ mates/ -Qh4 35.exf7 Ne7 36.Kxf1 Whites clear edge) 35.KxF1 Whites clear edge. / -f6 31.RxH3 fxg5 ( -Kxg6?/ -Rxh3?, guess why?) 32.BH5, RUINING Blacks position. SO, back to "main-line", if you don`t mind me saying so. (30.BxG6 Bxf1) 31.BxF7 (story continues...) -Ra1 ( -Rf6 32.Kxf1 retaining attack) 32.NE6+ Rxe6 ( -Kf6 33.Qg5+ mates in 2/ -Kh7 33.NF1+ mates in 1, but NOT 33.Nxc7?? Bh3+ mates/ -Kh8 33.Qxh6X) 33.QG5+ Kf8 ( -Kxf7 34.Rf3+ mates in a few moves also) 34.Qg8+ Ke7 35.Qe8+ followed by mate soon. |
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| Jan-23-10 | | Halldor: <paul1959> LOL! You are right. Such things happen in my games! |
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| Jan-23-10 | | ChessKnightsOfLondon: This is very tough, i'm almost stuck for ideas but I think i'll take a chance and play Bxg6. If black takes the room i'll take on f7 with the bishop and have a decent attack. If he takes the bishop with the rook i'll take his bishop with my rook and have a slight attack on the H file. Can't be sure if this is winning though. |
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| Jan-23-10 | | ZZer: Really good puzzle! Although Black needs just one move to win, White's attack won't let it happen... |
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| Jan-23-10 | | gofer: I think this sort of play should be called a "kitchen sink" attack. Where one player
throws absolutely everything at their opponent until he has nothing left to throw but
the "kitchen sink"...
There are a couple of things to notice...
1) That once black is allowed to play Bxf1 and follows it up with Ra1, then black has
real threats of Bh3#, but white has 3 moves before that scenario plays out and a lot
can happen in 3 moves...
2) What alternatives does black have to the aforementioned attack? Not much, Q and N
are busy trying to stop Pc6. Rh6 is busy trying to protect Pg6 but as we shall see his
valiant efforts are for nought...
3) White really wants to play Ne6+ winning the queen, but actually there is another motive,
it opens the g file and also the c1-h6 diagonal to attack the king. Obviously the
immediate Ne6+ is a little premature as then Bxg6 Rxf6+ is not so great for white. But it
is always there lying around as a little treat for white to play... 30 Bxg6 ...
Option 1 (the dull slow loss)
30 ... Rxg6
31 Rxh3 ...
31 ... Rxg5 32 Qxg5 Kf8 33 Rh8#
31 ... f6 32 Rh7+ winning
31 ... Ne7 32 Kh8 winning
31 ... Qe7
32 Rg3 ...
and now black is a miserable position having lost any threat against white and
with white about to play f4 (or h4 or kh1) and blacks attempts all have no teeth
(i.e. 32 ... g6 33 Ne6+ Kf7/Kh7 34 Rxg6 Kxg6 35 Kh1 winning) Option 2 (the fun one)
30 ... Bxf1
31 Bxf7 ...
I hope this is the correct continuation, white has gained two pawns for his rook, but
importantly still has R, N, B and Q bearing down on the black king and now we can throw away
B and N or B and R and still have a mating combination! 31 ... Ra1 (hoping for Bh3# at some point)
32 Ne6+ ...
32 ... Kf6 33 Qxh6+ mating
32 ... Kf6 33 Qxh6+ mating
32 ... Kh7 33 Bg8+ Kxg8 34 Qg5+ Kh7 35 Nf8+ Kh8 36 Qxh6 Kg8 37 Rg3+ Kf7 38 Qe6+ Kxf8 39 Rg8# 32 ... Kxf7
33 Rf3+ Rf6 (K anywhere allows Qg5+ or Qc7+ winning)
34 Rxf6+ Ke7 (Kxf6 35 Qg5+ mating)
35 h4 Bh3+
36 Kh2 Bxe6 (Kxf6 37 Qg5+ mating)
37 Rxe6+ Kf7 (Ke8 37 Qg5+ Ne7 38 Rxe7 Qxe7 39 c7+ winning and Kf8 37 Qh6+ Qg7 38 Re8+ winning)
38 Qh6 with mate to follow...
32 ... Rxe6
33 Qg5 Kxf7 (Kf8 34 Qg8+ mating and Kh7 34 Qg8+ Kh6 35 Qh8+ Kg5 36 Rg3+ Kf4 37 Qh4+ Kf5 38 Bxe6#)
34 Rf3+ Rf6 (Ke8 35 Qg8+ Ke7 36 Rf8#)
35 Rf6+ Ke7 (Ke8 38 Qg8+ Ke7 37 Qf8#/Rf7#)
36 Kg7+ Kd8/Ke8
37 Rf8#/Qf8#
Time to check what really happened on move 31 or whether I was correct! ... |
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| Jan-23-10 | | Utopian2020: Got it. |
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| Jan-23-10 | | johnlspouge: Saturday (Very Difficult)
Krasenkow vs M Markovic, 1990 (30.?) White to play and win.
Material: Even. The Black Kg7 has 4 legal moves and Is vulnerable to Ne6+. Thus, Pf7 is burdened, and Pg6 is guarded only by Kg7 and Rh6. The White Rb3 x-rays Bh3 through the White Bd3, suggesting a discovered attack, possibly 30.Bxg6. Similarly, the White Qd2 x-rays Rh6 through the White Ng5. White has an advanced passed Pc6, blockaded presently by Qc7. The Black Bh3 threatens 30…Bxf1. The White Kg1 is secured from check. Candidates (30.): Bxg6
30.Bxg6
Black must capture something or accept loss of a P.
(1) 30…Rxg6 [fxg6 31.Ne6+ wins Qc7] [Kxg6 31.Rxh3 wins a P and exposes Kg6] 31.Rxh3 Qe7 32.Rg3
White has won a P.
(2) 30…Bxf1 31.Bxf7 (threatening 32.Kxf1 or 32.Ne6+)
Black cannot afford to lose Bf1 without material compensation. 31…Ra1 [withdrawing Bf1 is clearly worse in the variations below] 32.Ne6+ Rxe6 33.Qg5+ [dxe6?? Bh3 and # soon]
(2.1) 33…Kxf7 34.Rf3+
(2.1.1) 34…Rf6 35.Qxf6+ Kg8 [Ke8 36.Qf8#]
36.Rg3+ Kh7 37.Kh7 [Qg7 38.Qxg7#] Qg8+ 38.Kh6 Qg6#
(2.1.2) 35.Ke8 35.Qg8+ Ke7 36.Qxe6+ Kd8 37.Rf8#
(2.2) 33…Rg6 34.Qxg6+ Kf8 [Kh8 Qh6#]
35.Qg8+ Ke7 36.Qe8+ Kf6 37.Rf3+ Kg5 [Kg7 38.Qg8+ Kh6 39.Qg6#] 38.Qg8+ Kh4 [Kh6 39.Qg6#] Qg3#
(2.3) 33…Kf8 34.Qg8+ Ke7 35.Qe8+ Kf6 36.Qxe6+, etc., as above (2.4) 33…Kh7 [Kh8 34.Qg8#]
34.Qg8+ Kh6 35.Qh8+ Kg5
36.Rg3+ Kf5 [Kf4 37.Qh4+ Kf5 38.Qg5+ Ke4 39.Qg4#]
37.Qh5+ Kf6 [Ke4 38.Qg4#] [Kf4 38.Qg4#]
38.Qg6+ Ke7 39.Qxe6+ Kf8 [Kd8 40.Qe8#] 40.Qe8#
I missed the game defense 32.Kh7, but the basic theme is the same in all variations: White must keep checking to avoid ...Bh3#. Once Rb3 comes in on the K hunt, Black is dead. |
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| Jan-23-10 | | Patriot: I calculated 30.Bxg6 Bxf1 31.Bxf7 Ra1 and thought it was very dangerous for white and couldn't see a good follow-up if 32.Ne6+ since white has no time to capture the queen. OTB I would've played either 30.Nxh3 or maybe 30.Re1. Another concern was 30.Bxg6 Rxg6 31.Rxh3 f6 (taking advantage of the pin), but I didn't calculate further. As <gofer> mentions, 32.Rh7+ wins. |
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Jan-23-10
 | | Jimfromprovidence: <gofer> <30 Bxg6 Bxf1 31 Bxf7 Ra1 (hoping for Bh3# at some point) 32 Ne6+ Kxf7 33 Rf3+ Rf6 34 Rxf6+ Ke7> This is a very interesting position parsed from <gofer>'s post. 
click for larger viewWhite is still subject to mate in 2 if he does not move his h pawn. In addition, all other moves appear to lose for white (except 35 Qc3 which draws). So, if white moves the h pawn he wins easily; if not, he loses or draws. |
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| Jan-23-10 | | tacticalmonster: 1) f1 rook is under attack. White kingside has light square weaknesses 2) the protected passed c pawn tie down both the black knight and queen
and they are out of play
3) the g5 knight attacks both h3 bishop and e6 square 4) b3 rook has a discovery attack on the bishop. It can also switch to the kingside quickly (f3, g3 and h3) 5) White queen has a discovery on the h6 rook and attack kingside dark squares 6) black rook control the open a file that can attack white back rank candidate: Bxg6
a) 1 Bxg6 Rxg6 2 Rxh3 f6?? 3 Rh7+ Kg8 4 Rxc7 
b) 1 Bxg6 Bxf1 2 Bxf7 Ra1 3 Ne6+ Kxf7 ( 3 Rxe6 4 Qg5+ Kh7 5 Qf5+ Kh8 6 Qh5+ Kg7 7 Rg3+ Kf8 8 Rg8+ Ke7 9 Re8#) 4 Rf3+ Rf6 5 Rxf6+ Ke7! 6 h4 Bc4+ 7 Kh2 Bxd5 8 Qg5 c) 1 Bxg6 Bxf1 2 Bxf7 Qe7 3 Ne6+ Kxf7 4 Qxh6 Ra1 ( 4 Qf6?? 5 Rf3 ) 5 Rf3+ Ke8 6 Qh8 Qf8 7 Qxf8# |
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| Jan-23-10 | | johnlspouge: < <al wazir> wrote: [snip] But I'll never believe that Krasenkow calculated that -- along with everything else -- before starting his combination. > < <AccDrag> wrote: Why wouldn't you believe, al wazir? Checks tremendously cut down the branches of the calculation tree. A strong GM should be able to calculate that line quickly. > <AccDrag>, if you actually try to write down every variation to a P advantage, as I used to, you will realize that the effort usually becomes a pointless exercise in inevitability. Heavy piece attacks in particular become thematic: there are lots of variations, but they eventually boil down to whether an aggressor can keep checking. Either he has the resources or he does not, and it usually becomes apparent after a few moves into a few variations. Yes, some people can calculate every variation today within a clocked limit, but I am with <al>, because most people with that skill do not need to calculate every variation to its conclusion to know 30.Bxg6 is a win. I regarded my efforts today as overkill, an <agb2002>-style exercise for board vision. (Hi, Antonio ;>) <Patriot> raises an important relevant point, however: the moves 30...Bxf1 and 31...Ra1 are extremely dangerous. Such moves requires a lot of calculation to ensure that their threats can be neutralized. |
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| Jan-23-10 | | wals: Check the wizard out
http://en.wikipedia.org/wiki/Micha%... |
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| Jan-23-10 | | VincentL: In this "very difficult" position, the move that suggests itself to me is 30. Bxg6 Now:
(a) 30......fxg6 31. Exh3 and black will lose material. After 31.... Rxh3 32. Ne6+ winning the black queen, leaving white with Q for R. After 31.....Qe7/Qd8 32. Ne6+ followed by 33. Qxh6 again leaving white a rook up. After 31.....Kg8/Kh8 32. Rxh6 again leaving white a rook up. After 31-.... Kf8 32. Ne6 winning the black queen for nothing. (b) 30.....Rxg6 31. Rxh3. Now perhaps 31....Qe7. I am not sure how to proceed. 32. Rg3 doesn't
seem to lead anywhere. Neither does 32. Rh7+
I am out of time, and am going to find out what happened. Maybe my first move is wrong. |
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| Jan-23-10 | | VincentL: Well, my first move is as in the game, but black played 31..... Bxf1. I didn't get as far as considering this, as I got stuck against 31.... Rxg6. No doubt the other posts will show how to proceed against Rxg6. Let's see |
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| Jan-23-10 | | VincentL: From the other comments I see that by (b) line above just leads to the win of a pawn and a positional advantage - according to <RandomVisitos>Rybka gives white +2.30 in this line, which should be decisive. With puzzles one never knows when to stop looking for more. |
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| Jan-23-10 | | cyclon: I found at least one mistake of importance in my own analysis concerning actually a game-line 32.Ne6+ KH7, where I claimed 33.Nf1+ mates in 1. That must be based on the assumption Whites Queen being in g5, whereas it`s being in d2 Whites game-continuation is correct - 33.Bg8+!. |
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| Jan-23-10 | | cyclon: <gofer:32 ... Kxf7
33 Rf3+ Rf6 (K anywhere allows Qg5+ or Qc7+ winning) 34 Rxf6+ Ke7 (Kxf6 35 Qg5+ mating)
35 h4 Bh3+
36 Kh2 Bxe6 (Kxf6 37 Qg5+ mating)
37 Rxe6+ Kf7 (Ke8 37 Qg5+ Ne7 38 Rxe7 Qxe7 39 c7+ winning and Kf8 37 Qh6+ Qg7 38 Re8+ winning) 38 Qh6 with mate to follow...> Well spotted variation. |
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| Jan-23-10 | | David2009: Saturday's puzzle Krasenkow vs M Markovic, 1990 White 30? What a fantastic combination! I had a quick look at this earlier this evening (short of time) and thought "I wonder. 30. Bxg6 is that rare creature -
a self-pin that comes good after ...Rxg6 31 Rxh3, meanwhile if Black grabs the f1 Rook I have 31.Bxf7 and an attack for
the sacrificed Rook. Hey, this is a puzzle - this must it - self-pins are really risky which explains the
difficulty rating". Feeling lazy I peeked at the game, coming back to it later. No credit since I hadn't even seen Black's
31...Ra1! which so nearly turns the tables. Thee are some wonderful variations, here is just one:
30.Bxg6 Bxf1 31.Bxf7 Ra1 32.Ne6+ Kxf7 (instead of Kh7) 33.Rf3+ Rf6! 34.Rxf6+ Ke7 35.h4! Qxc6 (what else?) 36.dxc6 Kxf6
click for larger view (a last throw of the chess dice) 37.Nd8! and wins. PS - I see <gofer> and <Jim> have beaten me to most of this variation. What a chess feast! |
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| Jan-23-10 | | amathus: hedgeh0g: What would be the probability of correctly guessing one's way through the entire combination? That is a very good question, starting with the probability of correctly guessing the first move?! |
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| Jan-23-10 | | avidfan: After 30.Bxg6 Bxf1 31.Bxg7, White blasts open the Black king position, awaiting the invasion by rook and queen. He is also under a mate threat after 31...Ra8-a1
click for larger viewSo 32.Ne6+ and the king tries to hide but is forced to take the Bishop after
32... Kh7 33.Bg8+ Kxg8. The Queen now
invades 34.Qg5+ but g7 and g6 is owned by White so no interceptions can occur. The king is forced to h7 since he has to protect R/g6. On 34...Kh7 35.Nf8+ he must go to h8 ...Kh8 then 36.Qxh6+ and again the Black queen cannot interpose at h7 which is guarded by N/f8. So 36...Kg8,
then 37.Rg3+ and he is forced to f7 because g7 is owned by White again. Finally 38.Qe6+ and Black resigns just before mate by rook at g8. |
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| Jan-23-10 | | zb2cr: Blast. All I considered was the tame response 30. ... Rxg6; 31. Rxh3 etc. I never even considered the game response. No credit for me. |
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| Jan-23-10 | | patzer2: The demolition sham sacrifice 30. Bxg6!! busts open Black's defenses, opens up a decisive attack on the resulting exposed King position, and solves today's Saturday puzzle. In the game line after 30...Bxf1, White must play accurately and precisely to maintain a decisive advantage. Two essential follow-ups include the surprise move 31. Bxf7! and the decoy sham sacrifice 33. Bg8+! |
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Later Kibitzing> |
Kibitzing
sac: 30.Bxg6