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|Sep-22-10|| ||TheBish: E Eliskases vs B Wexler, 1960|
Black to play (42...?) "Medium/Easy"
Faced with a series of checks beginning with 43. Qd7+, where White looks to have at least a draw, Black needs to act fast.
42...Qh1+! 43. Kxh1 Nf2+ 44. Kg2 Nxg4 simplifies to winning N+P endgame. Black will follow with 45...Nf6, either simplifying to a winning K+P endgame or queening the passed a-pawn.
|Sep-22-10|| ||dzechiel: Black to move (42...?). Material even. "Medium/Easy."|
White threatens checks with the queen that can keep the game going for a long while. If black wants to make progress, the queens have to come off of the board. To this end, he should play
42...Qh1+ 43 Kxh1 Nf2+ 44 Kg2 Nxg4
This is where black's slightly superior pawn structure (1 isolani and two islands vs 4 isolated pawns, doubled pawns and three islands, plus better king position) pay off.
Black can threaten the e- and c-pawns with his knight, and capture the white g-pawns with his king.
I think it's still a long slog, but black should win the end game.
Time to check.
Yup, now it's a matter of technique.
|Sep-22-10|| ||Once: <dzechiel> Excellent analysis, as usual, but one thing you said made me raise an eyebrow - white has three pawn islands?|
click for larger view
Now I have always countered doubled and isolated pawns as two separate pawn islands as they cannot defend themselves. So I would class it as four white pawn islands to black's two.
But I guess it's a question of definitions. And as we know chess terms are not always particularly precise. ;-)
|Sep-22-10|| ||gofer: The only question in my mind is whether black is totally winning in the following
position with white to move...
click for larger view
Black can easily stop Pg6 and Pg3 from promotion, where as white is going to struggle to stop black's Pd4 and Pa5!
Also Pc4 is in trouble after black plays Ne3! So yes I would go for the exchange!
42 ... Qh1+
43 Kxh1 Nf2+
44 Kg1 Nxg4
moving swiftly into a won end game... Time to check!
|Sep-22-10|| ||wladimirsky: Black has several advantages:
+ Outside queenside passed pawn. If all pieces were exchanged, the win would be elementary on account of this
+ White's pawns are very week, 4 pawn islands for White
+ White king could be in trouble given lack of space
Therefore, Black can win either it if finds immediate decisive threats to king or major exchanging operations where the outside pawn would carry the day.
I first lookt at 42...Nf2 but it does not seem to work on account of 43.Qd7+.
But change the move order and 42...Qh1 seems sufficient:
42....Qh1, 43.Kxh1 Nf2+, 44.Kg2 Nxg4, 45. Kf3 Nf6, 46.Nb6 Kxg6 etc.
Time to check...
|Sep-22-10|| ||agb2002: The material is even.
White might have some perpetual chances, or something more, with 43.Qd7+ Kxg6 44.Qg4+.
Black has two passed pawns and the white is far from them. This suggests 42... Qh1+, to eliminate White's counterplay chances and to make the most of the a- and d-pawns, 43.Kxh1 Nf2+ 44.Kg2 Nxg4 (threatens 44... Ne3+)
A) 45.Kf3 Nf6 (45... d3 46.Kxg4 d2 47.Nc3 a4 48.Kf3 a3 49.Ke2 a2 50.Nxa2 + -; 45... a4 46.Kxg4 a3 47.Nb4 d3 48.Kf3 d2 49.Ke2 + -)
A.1) 46.Nxf6 Kxf6 47.Ke2 a4 48.Kd2 a3 49.Kc2 d3+ 50.Kb1 d2 - +.
A.2) 46.g4 Kxg6 (46... Nxd5 47.exd5 Kxg6 (or 47... a4 48.c5 dxc5 49.d6 and Black loses his advantage) 48.c5 dxc5 49.d6 Kf7 50.g5 a4 51.g6+ + -)
A.2.a) 47.Nb6 Kg5 48.Nc8 (48.Na4 Nxg4 - +) a4 49.Nxd6 a3 50.c5 (50.Nf7+ Kh5 51.Nxe5 a2 - +) a2 51.c6 a1=Q 52.c7 Qf1+ 53.Kg3 Nxg4 54.Nf7+ Qxf7 55.c8=Q Qf2+ 56.Kh3 Qh2#.
A.2.b) 47.Nd7+ Kf7 48.Nc6 (48.Nd5 Nxd5 49.exd5 a4 50.c5 dxc5 51.d6 a3 52.g5 a2 53.g6+ Kxg6 54.d7 a1=Q 55.d8=Q Qf1+ 56.Kg3 Qf4+ 57.Kh3 Qh6+ 58.Kg4 Qh5+ 59.Kg3 Qg5+ 60.Qxg5+ Kxg5 - +) a4 49.Nb4 a3 50.Na2 Kg5 - +.
A.2.c) 47.Nc7 a4 48.Nb5 Kg5 49.Nxd6 a3 50.c5 a2 transposes to A.1.b.i.
A.3) 46.Nb6 Kxg6 47.Na4 (47.Nc8 a4 48.Nxd6 a3 49.c5 a2 50.c6 a1=Q 51.c7 Qf1#) Nd7 48.g4 (48.Ke2 Nc5 49.Nxc5 dxc5 50.Kd3 a4 51.Kc2 a3 - +) Nc5 49.Nxc5 dxc5 50.Ke2 a4 - +.
B) 45.Nb6 Nf6 46.Kf3 Kxg6 is similar to A.1.
C) 45.Nc7 a4
C.1) 46.Nb5 Ne3+ 47.Kf3 Nxc4 - +.
C.2) 46.Ne8+ Kxg6 47.Nxd6 a3 48.c5 a2 49.c6 a1=Q 50.c7 Kh5 51.c8=Q Qb2+ and mate next.
|Sep-22-10|| ||mrsaturdaypants: Perhaps doubled, isolated pawns should be considered more of an isthmus.|
|Sep-22-10|| ||swr: 42. … Ne1 and Nf2 lose to
43. Qd7+ Kh6 44. Qh7+ Kg5 45. Qh4#
So black must play 42. … Qh1+ 43. Kxh1 Nf2+ 44. Kg2 Nxg4, and should win easily with two passed pawns on the Q-side.
|Sep-22-10|| ||Marmot PFL: Easy week so far.|
|Sep-22-10|| ||desiobu: 42...Qh1+ 43. Kxh1 Nf2+ 44. Kg2 Nxg4 leads to a better endgame for black with g6 falling and the outside passer.|
|Sep-22-10|| ||ashvalkyrie: hm, I went for Nf2, but this leads to a perpetual (I believe) ..|
|Sep-22-10|| ||twin phoenix: <Once> you cracked me up! Don't blame the officers! Blame the politicians for getting them ol' pawns into a no win war!|
|Sep-22-10|| ||chrisowen: If it dog gone knight think Bernardo Nd3 f2 Nxg4 hounds up g3. HQ Qh1 is rum punch Eliskases splays the buck black nips a cask. Examine trail dig pawn attack unleash d3 homeward bound Ka5 cant rescue in time.|
|Sep-22-10|| ||kevin86: I didn't see and checks that led to anything-then I saw the perforce exchange of queens via the sac and fork.|
Black wins the ending without much difficulty.
|Sep-22-10|| ||YouRang: I pretty quickly realized that black would be sitting pretty if he could simplify, thanks (mostly) to the passed outside pawn.|
Just as quickly, 42...Qh1+ made sense, forcing a queen exchange. I didn't follow it any deeper than that, but I'm satisfied that the rest of the game would be a breeze for black.
|Sep-22-10|| ||EXIDE: Got it. After queens are removed this is a winning position for black, because white's knight is tied down preventing black pawn from moving forward. Three in a row this week, now wait for the difficult ones.|
|Sep-22-10|| ||DarthStapler: I considered it but I didn't think it gave a big enough advantage to win|
|Sep-22-10|| ||Once: <mrsaturdaypants: Perhaps doubled, isolated pawns should be considered more of an isthmus.>|
Or an archipelago?
|Sep-22-10|| ||M.Hassan: "Medium/Easy" Black to move 42....?
The pawn on a file could be promising for Black. Because it is an isolated pawn, advance of it towards the first rank can get White forces toward itself to prevent its promotion. IMO, Black can get advantage of this phenomenon but needs to do some "preparatory" work such as:
I think from here and on the march of the White king towards a file continues and meanwhile Black King can eliminate e pawn and White gets progressively weaker because of the separated pawns that he has until he resigns.
Time to check
|Sep-22-10|| ||ZUGZWANG67: We've been experiencing the "Endgame-Where-Material-Is-Equal-Festival" for a couple of weeks, now! Black has 2 good passed pawns: one protected, while the other is an outsider. White's are no good: they're doubled and the BK is there. Black is better.|
Obviously Black has a tactic at f2, namely ...Nf2, but the question is: Should B play ...Qh1 before or not? I think that 42...Nf2, threatening 43...Qh1+ mate, is flawed, as it offers White counterplay: 43.Qd7+ Kxg6 (anything else would be very dangerous) 44.Qe6+ and I think W might have perpetual.
So 42...Qh1+ 43.Kxh1 Nf2+ 44.Kg2 Nxg4 45.Kf3;
Black has the better Ks + pawns endgame.
45...Ne3!; This (temporary) pawn sacrifice should be enough for a win:
a) 46.Nxe3 dxe3 47.Kxe3 Kxg6!; The point is that White has no invasion square unless he goes after a5, which is way too far, as B would have enough time to win on the K-side. For example, W needs 5 tempi to win the a5-pawn, while during that time B plays ...Kg5-g4xg3-f3xe4. In other words, 48.Kd3 Kg5 49.Kc3 (49.c5 dxc5 50.Kc4 a4) 49...Kg4 50.Kb3 Kxg3 51.Ka4 Kf3 52.Kxa5 Kxe4. And now 53.Kb5 Kd3 and White can't attack d6 unless he gives up c4. But if, instead of going after a5 W defends his K-side then at some point ...a4 closes the deal.
But there's also (b), which is a little more complicated: 43.Nb6!? Kxg6 44.Kf2 Kg5 45.Kf3 Kh5! 46.Ke2 (46.Kf2 Kg4) 46...Kg4 47.Kf2 Kh3 (very interesting would be 47...Nd1+!? 48.Ke2 Nc3+ 49.Kd3 Kxg3 50.Nc8 (counterplay), for example 50...a4 51.Nxd6 a3 52.c5 (certainly 52.Kc2, but the d4-pawn would then eventually have it's day) 52...a2 53.c6 a1Q 54.c7 Qa6+! and mate to follow) 48.Kf3 Nf1 (49.g4 Nh2+; 49.Na4 Nxg3; 49.Nc8 a4). Maybe I went too far in my work, as I had to move pieces at some point in (b). There might be some flaws, but I think that the solution to today' puzzle revolves around something like 42...Qh1+ 43.Kxh1 Nf2+ 44.Kg2 Nxg4 45.Kf3 Ne3.
Time to check.
I think that this is the 1st time I'm so accurate in something that lasts for so long after the original position. It feels good!
|Sep-22-10|| ||wals: Yes, three in a row, but unfortunately not calculated to the end.|
White: depth 24:
1. = (0.00): 35.Qa2 Qd8 36.Qa1 g5 37.Qf1 Qxa5 38.Nd5 Qd2+ 39.Kg1 Nd7 40.Qf5 Qe1+ 41.Kh2 Qe2+ 42.Kg1 Qe1+ 43.Kh2 Qe2+ 44.Kg1 Qe1+ 45.Kh2 Qe2+ 46.Kg1 Qe1+ 47.Kh2 Qe2+ 48.Kg1 Qe1+ 49.Kh2 Qe2+ 50.Kg1
2. = (0.00): 35.Qa1 Qd8 36.Qa2 Qd7 37.Qa1 Qf7 38.Qd1 Qb7 39.Qe1 Qb8 40.Qd2 Qc7 41.Qg5 Qxa5 42.Qe7+ Kh6 43.Qf6 Kh7 44.Qf7+ Kh8 45.Qe8+ Kg7 46.Qe7+ Kh6 47.Qf6 Kh7 48.Qf7+ Kh8 49.Qe8+ Kg7 50.Qe7+
White: Depth 20:
1. (-1.57): 39.Nc6 Nxd3 40.hxg6 Qf2+ 41.Kh3 Qf1+ 42.Kh2 Qf6 43.Qd7+ Kxg6 44.Qg4+ Kh7 45.Qd7+ Qg7 46.Qxd6 Nf2 47.Kg2 Ng4 48.Kf3 a4 49.c5 a3 50.Qe6 d3 51.Qf5+ Qg6 52.Qxg6+ Kxg6 53.Nb4 Kf7 54.c6
White: Depth 25:
1. (-2.92): 40.Qe2 Nc5
2. (-3.71): 40.Nc7 Qxc7 41.Qxg6+ Kf8 42.Qe6 Qe7 43.Qg6 a4 44.h6 Ne1+ 45.Kh3 Nf3 46.Qf5+ Qf7 47.Qc8+ Ke7 48.Kg4 Nh2+ 49.Kg5 Qf6+ 50.Kh5 Qf8 51.Qc7+ Kf6 52.h7 Nf1 53.Qxd6+ Qxd6 54.h8Q+ Ke7 55.Qh7+
White: Depth 23:
(7.10):45.Kf3. no better. Nb6 just as bad.
White resigned move 54.
If played out the game may have progressed:-
depth 26 : time 22 min:
1. (-#14): 55.Na4 Kxe4 56.Kb5 d2 57.Nb2 Kf4 58.Kc4 e4 59.Kd4 e3 60.Kc3 d1Q 61.Nxd1 Nxd1+ 62.Kd3 Nf2+ 63.Kd4 e2 64.Kc4 e1Q 65.Kc5 Ke5 66.Kb5 Kd4 67.Ka4 Kc4 68.Ka3 Qa1#
2. (-#14): 55.Nb3 Ke3 56.Ka4 Nxe4 57.Na5 d2 58.Nc4+ Ke2 59.Nb2 Nf2 60.Ka3 Nd3 61.Na4 Ke3 62.Nc3 Nf2 63.Ka2 Kd3 64.Na4 d1Q 65.Nb2+ Kc2 66.Nxd1 Nxd1 67.Ka3 Kd3 68.Kb4 e4 69.Ka5 e3 70.Kb6
|Sep-22-10|| ||LIFE Master AJ: I set this up on ChessBase, and stared at it for nearly an eternity ... |
The problem was that I did not notice it was "Black to Play" and "42...?" (I was looking at it as a "White to Play" problem!)
I got it out to Black's 46th move. I thought that Black was winning, however, I was not 100% sure, as Knight endings can be very tricky.
|Sep-22-10|| ||karnak64: The opening combination was easy -- swap queens and win a pawn. But the rest -- well, as the last chap said, "Knight endings can be very tricky."|
I guess I'd have given it a shot OTB, but on speculation rather than calculation.
|Sep-22-10|| ||icky: I guees the correct move but not totally visualize moves til end of the game,excellent analysis instead of Qxg6 he did Qf2+,Black a-pawn is a winning piece and also White have two isolated pawn in c and e rank.it was a good end game calculation.|
|Sep-23-10|| ||turbo231: The first move was easy enough to see, of coarse the continuation was much harder.|
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