| Sep-18-14 | | Lighthorse: Wait, why does Black resign? Doesn't 32...Ra5 save him?
[33.Qxa5 Qxe4 and sure his King is still precarious but he's also still a Bishop up so might be able to save it.] |
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| Sep-18-14 | | Olsonist: Worse than precarious. QxR, QxN, Qa7+, Kc8, Qa8+, Kd7, QxR |
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Sep-18-14
 | | agb2002: White has a knight for a bishop and a pawn.
Black threatens ... Qxb2.
Four attackers (queen, rook, knight and the pawn on a4) against zero defenders looks good for White and invites to play 26.Rb5+ to pave the way for the other pieces: A) 26... cxb5 27.Qd6+ Ka7 28.axb5 a4 (28... b6 29.Qc7#; 28... Qxe4 29.Rxa5#) 29.Nc5 (threatens 30.b6#) 29... Qb3 (29... b6 30.Qc7#; 29... Qxb2 30.Rxa4#) 30.Nxb3 and mate next. B) 26... Ka6 27.Nc5+ Ka7 28.Rxb7#.
C) 26... Ka7 27.Rxa5+ Kb6 28.Rb5+ cxb5 (28... Ka7 29.Qc7 and mate in two) 29.Qd6+ Ka5 (29... Ka7 30.axb5+ Qa4 31.Rxa4#) 30.axb5+ Qa4 (30... Kxb5 31.Qc5#) 31.Rxa4+ and mate in two. |
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| Sep-18-14 | | Viennablue: Lighthorse, after 34. Qa7+ Kc8 35. Qa8+ Kd7 36. Qxh8 I can fully understand blacks desire to leave the board... |
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| Sep-18-14 | | plumbst: Medium. White is down a pawn.
The most noticeable thing about the position is Black's vulnerable king and scattered pieces. Despite this, it looks a sacrifice is needed to break through. 26.Rb5+!
If 26...Ka6, 27.Nc5+ Ka7 28.Rxb7#
If 26...Ka7, 27.Qc7 cxb5 (now this is forced) 28.Nc5 Bd5 (or c8) 29.axb5 forcing mate. So, 26...cxb5.
27.Qd6+ Ka7
28.axb5 a4 (28...b6 29.Qc7#)
29.Qc5+ Kb8
30.b6 Ra5 (30...Rc8 31.Qd6+ mating; 30...Ra6 31.Qe5+ mating)
31.Qxa5 Qxe4 (Qe5+ was still threatened)
32.Rxa4! (threatening Qa8#) Kc8
33.Qc5 Qc6 (33...Kd7 34.Qc7+ mating)
34.Qxc6+ bxc6
35.Ra8+, winning the Rook with an easy win.
Edit: Ah, missed the 30.Qe5+ mate, but the endgame is winning enough for me, ha. |
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| Sep-18-14 | | Pedro Fernandez: The first 8 plies are easy to find out and this is my whole variation:
26.Rb5+ cxb5 27.Qd6+ Ka7 28.axb5 a4 29.b6+ Ka6 30.Nc5+ Ka5 31.Nxb7+ Ka6 32.Nc5+ Ka5 33.Nxa4 Ka6 34.Qc7 Ka5 35.b7+ Kb5 36.Qb6 mate.
click for larger view |
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| Sep-18-14 | | diagonalley: well, i did take a look at 26.R-QN5+ but couldn't make it work :-( |
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| Sep-18-14 | | gofer: <26 Rb5+ ...>
26 ... Ka6?
27 Nc5+ Ka7
28 Rxb7#
26 ... Ka7
27 Qc7 cxb5 (Bc8/Rb8 28 Rxa5#)
28 axb5 a4
29 Nc5 mating by either b6+ or Rxa4+
<26 ... cxb5>
<27 Qd6+ Ka7>
<28 axb5 ...>
28 ... Qxe4
29 Rxa5#
28 ... b6?
29 Qc7#
<28 ... a4>
<29 Nc5 ...>
29 ... Qb3
30 Rxa4 b6#
<29 ... Rac8>
<30 Nxa4! ...>
At this point black can resign, white's attack is akin
to the Vogon Destructor Fleet's demolition of earth... <Resistance is useless!> <30 ... Rc6>
<31 bxc6 ...>
click for larger viewWhat are black's chances from here? ZERO
One nice finish possible finish is...
31 ... Rc8
32 cxb7 Kxb7
33 Qb6+ Ka8
34 Nc5+ Qa4
35 Qb7#
another is
31 ... Qb3?
32 Nc5+ Kb6
33 Nxb3 cxb3
34 cxb7+ Kb5
35 Ra6 Kc4
36 Qd4+ Kb5
37 Rb6+ Ka5
38 Qb4#
~~~
Yep... |
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| Sep-18-14 | | hedgeh0g: I calculated 29.Nc5, intending to follow up with b3! (a similar idea to the 29.Qc5+ variation) which should also be winning. |
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| Sep-18-14 | | Pedro Fernandez: SF5 x64 finds mate in 17 analyzing about 2 billion nodes in 3'30". My PC: i7-4790k @ 5 GHz, watercooled (C*****r Hydro H105), 4x8GB DDR3 @ 2400 MHz, 2x S*****g 840 Pro in RAID 0 array, analysis speed: 10,000+ KB/s (avg.). I think a strong GM (2700+) finds the mate more quickly. |
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| Sep-18-14 | | Pedro Fernandez: Typo: 10,000+ kN/s, sorry. |
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| Sep-18-14 | | morfishine: I started with <26.Rb5+> cxb5 27.Qd6+ Ka7
28.axb5 a4 and thought <29.b6+> was the way to go ***** |
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| Sep-18-14 | | zb2cr: I saw the first three moves for White, but not the forced mate given in notes. |
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| Sep-18-14 | | patzer2: For my Thursday solution, duplicated White's line up to 26.Rb5+! cxb5 27.Qd6+ Ka7 28.axb5 a4 29. Qc5+ Kb8 (position below)
click for larger viewHere I deviated slightly with 30. b6! (transposing to White's 32. b6!). If Black wishes to continue (instead of resigning as in the game), White wins easily after 30. b6! Ra5 31. Qxa5 Qxe4 32. Rd1! Qf4 33. Rd4!  . P.S.: Like White, I missed the forced mate 30. Qe5+! Ka7 (30... Kc8 31. b6 Kd8 32. Qd6+ Bd7 33. Qf6+ Ke8 34. Nd6+ Kf8 35. Qxf7#) 31. b6+ Kxb6 32. Qc5+ Ka6 33. b4 b6 34. b5+ Kb7 35.
Nd6+ Kb8 36. Qxb6#.
However, as a practical matter, the prospect of immediate resignation after either 30. b6! or 32. b6! (by transposition) is IMO as good an option as the 30. Qe5+! mating line. |
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| Sep-18-14 | | patzer2: <Pedro Fernandez: The first 8 plies are easy to find out and this is my whole variation: 26.Rb5+ cxb5 27.Qd6+ Ka7 28.axb5 a4 29.b6+ Ka6 30.Nc5+> After 30...Kb5, does White still have a win? Maybe 30. Qb4! is a good alternative. |
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Sep-18-14
 | | Once: For all it is a game about calculation, chess is also about fuzzier logic. The look and feel of a position. The funny feeling you get when something looks wrong, but you can't quite explain why. A stirring in your loins when something looks right. Show our starting position to a bunch of chess players and I expect that most of them would notice the uncomfortable positioning of the black king on b6. He doesn't look happy there. It is somewhat demeaning for a Royal personage to be mingling with the proles. But what to do about it? If we are black, we want to retreat our king to somewhere safer. If we are white, we want to torture him some more. So you might think to play 26. Qe3+
click for larger viewIt's a check, and checks are usually good. They might even be mate. It can't be (sensibly) blocked. But something is not quite right. The problem with 26. Qe3+ is that it allows the black king to scurry to c7. We really want to keep him in the open. For all 26. Qe3+ is initially attractive, it soon dawns on you that the queen really needs to keep an eye on the b8-h2 diagonal. So we cast around for other tempting first moves. There is a certain perverse devil-may-care satisfaction in an exchange sac. But 26. Rxd6 doesn't achieve much. The bishop wasn't doing anything important. The white knight? He can't attack anything juicy. There are no fork pairs. He's on a good square as he is. That leaves the two rooks. The stay at home Ra1 isn't doing much for his living, but it's hard to see how to get him into the action. Sooner or later you spot 26. Rb5+!. This is a move that feels right. It may have a fatal flaw somewhere in one of the variations, but for now it fits like one of those favourite pairs of jeans - the ones that you have worn so long that they feel like a second skin. Depending on your age, they either hug you in all the right places or sag where you sag. And the reason that 26. Rb5+ feels right is because of 26...cxb5 27. Qd6+ 
click for larger viewThere is something immensely satisfying about checking your enemy king with a queen from just two squares away. Especially if he is hemmed in by epaulette pawns or pieces. It feels right. Snug. Then 27...Kh7 28. axb5
click for larger viewGiving the Ra1 something to do. As our transatlantic cousins would say, it's his "jawb". Fast forward to our near final position:
click for larger viewAnd here I have to take issue with the annotation to the game. 30. Qe5+ may be a faster mate, but 30. b6 feels like the move that the position demands. Nailing the king's coffin down. Giving the b pawn a jawb. Mind you, there is a problem if you try to play chess entirely on gut feel and instinct. We need to do some of that calculating stuff some of the time. <Breaking news - since making my book free from yesterday, 111 people have downloaded it. Many thanks to everyone who's done that.> |
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Sep-18-14
 | | Penguincw: Maybe a tad too easy for a Thursday. Although I did not solve the whole thing, I did get 26.Rb5+ cxb5 27.Qd6+ Ka7. |
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| Sep-18-14 | | waustad: After seeing the first few moves I was trying to get the knight into the fray but didn't see how. |
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Sep-18-14
 | | kevin86: I saw the germ of the solution, but I couldn't make it all the way through. |
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Sep-18-14
 | | Jimfromprovidence: <Lighthorse> <Wait, why does Black resign? Doesn't 32...Ra5 save him? [33.Qxa5 Qxe4 and sure his King is still precarious but he's also still a Bishop up so might be able to save it.]> In this text variation beside 34 Qa7+ white also has 34 Rxa4. 
click for larger view The threat is 35 Qa8#. This forces 34...Kc8. 35 Qc5+ Qc6 36 Qxc6+ bxc6 37 Ra8+ Kb7 38 Rxh8 follows. 
click for larger viewWhite will end up ahead a rook plus two pawns vs. bishop and a easy win ahead. |
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| Sep-18-14 | | Pedro Fernandez: <<patzer2>: <Pedro Fernandez: The first 8 plies are easy to find out and this is my whole variation: 26.Rb5+ cxb5 27.Qd6+ Ka7 28.axb5 a4 29.b6+ Ka6 30.Nc5+> After 30...Kb5, does White still have a win? Maybe 30. Qb4! is a good alternative.> Yeah <patzer2>, you're right! Indeed I knew that my variation not necessarily was the optimal one i.e. the black can have a better defense. After all I got my variation in about 6 min. (no machines). Greetings! |
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| Sep-18-14 | | WDenayer: I found 26.Rb5 immediately. If there's only one move in a position, play it. White checks on d6 and the pawn on b5 - b6 will cause havoc. I couldn't calculate it till the end, but it is not necessary. |
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Sep-18-14
 | | Bubo bubo: I also found 26.Rb5+ immediately, but in the main variation 26...cxb5 27.Dd6+ Ka7 28.axb4 I missed the obvious 28...a4 - instead I thought that Black could avoid mate there only by playing something like Qc1+, and turned to the calculation of 26...Ka7. Therefore at best some consolation points for me today :-( |
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Kibitzing
sac: 26.Rb5+