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| Oct-08-10 | | CHESSTTCAMPS: In this ending, the pawn count is even, but white has a knight for a bishop and a kingside pawn majority. This position has technical and tactical aspects. Technically, in general, white would like to put pawns on light squares as much as possible, to make them inaccessible to the black bishop and to control squares that the DSB can't control. Also, a king and pawn ending after a minor piece exchange will favor white because of the pawn majority. Tactically, the black a-pawn is hanging, so the immediate question is whether or not white should grab it, given that the natural retreat squares b3 and c4 are controlled by black pawns. After 34.Nxa5 Ke6 35.a4 Bc7 36.Nc6 bxa4 (or 36.Nb7 Ke5), the knight is trapped in enemy territory. This suggests that before grabbing the pawn, white first should try to secure the safe retreat square c4: 34.a4!
This minority attack accords with the technical principles mentioned in the initial summary and degrades the black queenside pawn mass by attacking the light squares, effectively exploiting the disadvantages of the bishop. A) 34... ba 35.Nxa5 Ke6 36.Nxc4 Bc7 (else Nb6 wins a 2nd pawn) 37.Kd3 Kd5 38.f3 followed by Nd2 and e4+, after which the white king will be able to invade on light squares. This looks like a straightforward win. B) 34... Ke6 35.axb5 Bc7 36.e4! (stronger than 36.f3, because it immediately opens a path for the white king) fe 37.Ke3 Kf5 38.g4+ Ke6 39.Kxe4 a4 (Kd6 40.Ne5) 40.g4 h6 41.f3 (black is in zugswang) Bd6 44.Na5 wins the c4 pawn and the game. B.1) 34... Kd5 35.g4! (higher priority than the a-pawn) fxg4 (f4 36.Kf3 is no better) 36.hxg4 Bf7 37.Kf3 a4 38.e4+ Ke6 39.Ke3 Kd7 40.Kd2 Kc8 41.Kc2 Kb7 (otherwise the maneuver Kc1-b1-a2-a3 win) 42.e5 Kb6 43.e6 Kxb5 44.e7 Bxe7 45.Nxe7 wins. Time to see how Bronstein played it. |
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| Oct-08-10 | | Eduardo Leon: 34.♘xa5 is bad because of 34...♔e6 35.♘b7 ♗e7, and the knight is "boxed". Instead, we weaken the c4 pawn first: 34.a4!, and if 34...bxa4 or 34...b4, then 35.♘xa5 and 36.♘xc4. If black does not move his b pawn, then white will play 35.axb5 himself 1. winning a pawn, 2. which is passed, 3. is in a light square (and thus, invulnerable to eventual attacks from the bishop), 4. supports the knight, and 5. is far away from the king, which is also busy in the kingside. |
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| Oct-08-10 | | CHESSTTCAMPS: I didn't cover B.2)34...Bc7 thinking that it would just be a transposition of the other lines. It seems that Bronstein's play varied from the specific lines I looked at, but follows the same ideas. |
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| Oct-08-10 | | Eduardo Leon: I would have liked to see the following sequence:
<41...♗xe5 42.♘xe5 ♔xe5 43.b6> At last, white sacrifices his passed pawn to get an overwhelming advantage in the kingside. The queenside, where black will have a pawn majority (after the demise of the b pawn), is essentially locked. <43...♔d6 44.f4 gxf4+> Of course, 44...h6 45.f5 is even worse.
<45.♔xf4 ♔c6>
45...h6 is useless, as it cannot extend the h pawn's remaining lifetime, which is exactly three moves. <46.♔g5 ♔xb6 47.♔h6> 
click for larger viewIt will take white five moves to promote his g pawn (48.♔xh7 and four g pawn advances). In the same time, black cannot improve his position in the queenside significantly. Even if his own a pawn did not get in the way, all black could do in five moves would be capture white's two pawns, without advancing his own pawns. |
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Oct-08-10
 | | ajk68: A great example of widening the beachhead. |
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| Oct-08-10 | | CHESSTTCAMPS: <OBIT> <...Anyone who thinks otherwise is invited to try it out against Crafty using <David2009's> link.>
Yep, I fell into traps twice before a winning 3rd attempt. |
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Oct-08-10
 | | chrisowen: Bronstein eta gramophone steady comes out hoping parson bg5 it steal a march circumstance pied a terre backward pawn see majestic whinny. One 9..nc6 able worthy queen break through bishop opening advantage fly off. Why not 21..qd5? bottoms up gentle man Alberto looks bent out of shape after a4 Bc7? Semaphore she slant earn white nap, ply for black out this world. Strong affable David. |
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| Oct-08-10 | | ounos: Just to clear something up - I think it's wrong to say "black set up a cunning trap here", when his last 8 moves were basically forced. White himself chose this path (probably thinking it as a clear win long ago), only to run up to a inconvenient tactical point, which luckily was avoidable. |
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| Oct-08-10 | | CHESSTTCAMPS: <OBIT: <sshhhh>To describe the guys who say they found the answer in two seconds, I would use a word other than "talent". ...>
I certainly agree that not just "any B-player" would find the right move that quickly. Many of us who did find it were undoubtedly influenced by the fact that it's a puzzle position and the obvious capture might be wrong. I doubt that many GMs would calculate the tactics of the trapped knight in 2 seconds, although all would be aware of the possibility of a trap very quickly. Those who makes claims about how quickly they solve a puzzle should give a brief outline of the tactics they see. |
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| Oct-08-10 | | mortigi tempo: <OBIT> <To describe the guys who say they found the answer in two seconds, I would use a word other than "talent". (Hint: My word is eight letters long and starts with "b".) Sufficed to say, there are some definite technical points to this finish...> technical points? This endgame is a general idea. I'd save the technical bits for when actually playing. Two points to note that now the bishop has to perform two duties of guarding the b5 pawn from passing to promotion and also e5 square after a later f4. the black king is going to have to come over to the queenside to deal with passed pawn (and free up the bishop) and the white king will invade on the kingside. the position plays itself, eventually. in hindsight, im not the only one who thinks this is easyish. I just expect more for 3 stars difficulty. No doubt some feeding of my ego involved as well. I'll give you that, too. btw I had plenty of snarky comments in response to whatever the 8 letter word was, but I'll keep my :|. I apologize for my abrasiveness/rudeness/being insensitive. I thought I was the first one posting. and maybe technical points mean different things to you and me. it makes me think of making the most accurate move in a given position. which I often save for the board once I understand the idea behind the win. Also I just saw you commented again. Well I looked at the position. And immediately thought a4 for the reasons. White is threatening to take a pawn anyways. It weakens c4 pawn if black captures while white's position is basically the same. On the flip side, this <greatly> weakens black's postition. black's bishop looks miserable. It is very difficult to even imagine blacks bishop getting to the other side of the board at this point. That's a very bad thing. White's knight though is very mobile, and after a4 you can see it moving to many squares. especially c4. another thing to note, black's position is so miserable, that white can take his time in improving his position before he advances. That usually means a win. as it is, when I think about it. I already know these things. So when I analyze the first move that looks best "a4" already things are looking pretty grim for black. I mean that's what chess is, you see these sorts of position so much that it becomes second nature in a way. people who look at this position and says white is better say so for a reason. and gms, ims, fms, and amateurs can look at this position and say white is better. you don't even have to know why for sure in your head, you just know white is better or close to winning. If you deny that this is possible, then I guess no amateur would be able to play 1 min chess well. P.S. Bigheads??? |
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| Oct-08-10 | | mortigi tempo: to put it another way. over time you learn how to just naturally know how to convert an advantage of good night over bad bishop in a given situation. That's why the solution can come so fast to some people. In itself 34. a4 move is a thematic move not uncommon to disrupting black's queenside pawn formation. |
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| Oct-08-10 | | mortigi tempo: btw when I look at all I wrote, I guess I take it back about it being easyish. and when I think about it if you don't know some of the ideas behind the win or remember. Or see a4, then I guess this makes this very very hard. because then you'd have to work all of this out move by move which just sounds horrendous to me.... |
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| Oct-08-10 | | Patriot: I certainly did not foresee everything that would happen but chose 34.a4 over 34.Nxa5. And no, it didn't take me a few seconds. It was more like 5-10 minutes. If white could only trade the knight for bishop, the win would be easy. White would enjoy the kingside majority while black only has a crippled majority on the queenside which is only good defensively. But trading pieces doesn't seem to be on the menu. So I started looking at the obvious, Nxa5. 34.Nxa5 snags a pawn but now the black crippled pawn majority is even, which isn't much to say. For example, if white goes after c5 the bishop can retreat and defend. Or if white ever goes after b5 then ...b4 can be played. The nice thing about 34.a4 is that it has more to offer. For one thing it goes by the principle of attacking a pawn chain by going after the base pawn. After 34.a4, a5 is still hanging and 35.axb5 is threatened. 34...bxa4? 35.Nxa5 and now c4 hangs. On 34...Bc7, 35.axb5 looks like an interesting game. There are possibilities of Na7-c8 and pushing to b6. This was quite enough to see that 34.a4 is superior. |
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| Oct-08-10 | | tacticalmonster: 1) queenside majority vs kingside majority:
a) Black queenside was damaged and had doubled c-pawn. It is impossible to force a passed pawn if White plays a3. b) White has a healthy majority but Black has more space on the kingside. It is diffcult for White to force a passed pawn there 2) bishop vs knight
a) The bishop is hammped in by the c5 pawn. It could not find any weakness in White kingside. It coordinates well with the BK to control the e5 square. Ideally it wants to go to the a1-h8 long diagonal to put pressure on the c3-b2 pawn chain. b) The knight is well placed on c6 but it is vulnerable there. BK can play e6-d7 or e6-d5 to drive it away. The knight can play Nxa5 immediately but it would concede the e5 square allowing the BK to transfer to the queenside via e5-d5-c6. 3) kings activites:
a) BK is more active thanks to the kingside space advantage. Right now e4 and d5 square is in nobody's hand so it is ready to take control of those squares b) WK is passive thanks to the lack of kingside space. It is hammpered in in particalely by the e3 pawn and therefore: Candidate: 34 e4
a) 34...fxe4 35 Ke3 Kf5 36 g4+ Kf6 37 Kxe4-get the pawn back with a more active king b) 34...Ke6 35 Kf3 Kd7 36 Na7! (if 36 Nxa5 Kc7 37 exf5 Kb6 the knight is trapped) 36...b4 37 exf5 Be5 38 Nb5 Kc6 39 a4! White's knight escapes along with an extra pawn c) 34...f4 35 Kf3 h5 36 e5+! Bxe5 37 Ke4 Bc7 38 Kd5 Bb6 39 Nb8! Ke7 40 Kc6 Ba7 41 Na6 Black queenside pawns are falling |
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Oct-08-10
| | OBIT: <mortigi tempo>Well, my basic objection is just that this ain't some quick decision. Assuming you see both 34. Nxa5 and 34. a4, it's going to take awhile to decide which move you like better. I'll bet even Bronstein spent a good 10 or 15 minutes thinking about this decision, maybe not at move 34, but definitely sometime after the queen exchange. But then, Bronstein's liability is that he sometimes sees too much. Whereas most of us see only one or two ideas in a typical position, Bronstein's brain has 15 ideas clamoring for his attention, all screaming, "Pick me! Pick me!" Anyway, I think it is amusing to backtrack a bit and look at the moves leading up to move 34. From move 28 on, it looks like Bronstein's focus is completely on picking off one of the queenside pawns. So, he finally gets to a position where his opponent says, "Fine, take it," and Bronstein, "Eh, no thanks. Here, take my pawn instead." Typical Bronstein - what a flair for irony. :) |
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| Oct-08-10 | | Patriot: <OBIT> <Well, my basic objection is just that this ain't some quick decision.> Unless there is a time scramble, I completely agree. When there are choices like this it can make the difference in the game result. If there is plenty of time, 2 seconds just isn't enough time to weigh out your options. I agree with <mortigi tempo> from the standpoint that 34.a4 is a simple concept but there's no way I would make that move instantly during a long time control. This is a Friday puzzle so I was willing to give myself time to get a feel for which move was better. Similarly if I were playing a high stakes game or a game with long time controls, it's worth the effort to look for a while to make sure a move is best and that you cannot find a better one. Otherwise you're not managing your time effectively. |
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| Oct-08-10 | | Everett: After seeing some amazing endgames by Bronstein recently, it seems clear that he was not weak(relative to his amazing opening and middlegame play) in this area. It is possible, however, that he didn't relish homework, and appreciated having the struggle begin and end entirely OTB. Again, perhaps this is one of a few reasons why he greatly enjoyed speeding up play and making time controls more flexible with the Bronstein clock. |
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| Oct-08-10 | | mortigi tempo: <OBIT> OTB tough decision and you second guess yourself and you have to analyze. here in the now, chess games puzzle of the day. It's white to move and  . No more no less. This is a huge hint. Look for the move that you would give a "!" to. And it's probably not going to be the obvious move.-- In retrospect, I deeply regret taking that tone in the first post. and regret posting even more. and really how long it took me to solve it was nobody's business but my own. and I didn't anaylze both moves. To immediately think nxa5 I couldn't say either way in the moment if it was good or not. But when I looked at a4 I immediately thought it was winning/ the only move. Maybe it was bad of me to think like this but as I wrote my comment my confidence only grew. I don't know what to tell you other than that I'm being honest and that for me it was the only move by a longshot. Probably it was just luck that I remembered. that and I think I saw it demonstrated recently on Dennis Monokroussos's blog in an analyzed game. So that idea was probably somewhat fresh in my mind. I found it. http://www.thechessmind.net/storage... the game Berbatov,Kiprian (2461) - Chatterjee,Debaraj (2288). Seeing that game kept the idea of saccing a pawn in the endgame fresh in my mind. I'm not sure why I'm still trying to convince you. And you do have very valid points. <Patriot> also makes very good points, too. And I'm inclined to agree with his last post. |
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| Oct-08-10 | | Helios727: How does white push for the win after 34. a4 bxa4 35. Nxa5 Be7 36. Nxc4 Bf8 ? |
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| Oct-08-10 | | Eduardo Leon: <Helios727>, I guess you meant 36...♗d8. If 36...♗f8, then simply 37.♘b6 and 38.♘xa4. |
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| Oct-08-10 | | CHESSTTCAMPS: <<mortigi tempo> <..In retrospect, I deeply regret taking that tone in the first post. and regret posting even more. and really how long it took me to solve it was nobody's business but my own. ...>> Don't worry about it - keep posting! A number of people who post in this forum like to report that they solved a problem almost instantly and I'm sure that it is often true. But keep in mind that is one thing to find the correct candidate quickly by intuition, knowledge and/or experience, but it usually requires more effort to properly verify that your candidate is correct (or otherwise) and follow it through to a result. Just curious - did you try playing the position against the Crafty link provided by <David2009>? |
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| Oct-09-10 | | goldenbear: <OBIT> Concerning your response to <shhhh>: Do you think Bronstein "calculated" the difference between Nxa5 and a4. Of course not. No doubt he solved this by analogy, as I did. It took 2 seconds, and my certainty of the solution's correctness could only have eroded after lengthy calculation. To be honest, in a live game I probably would have played a4 instantly even if the bishop were on f8. I have found that calculating when there is no need is a common source of my blunders. Besides, is calculating even possible in these kind of endings? There are so many possible variations, I wouldn't even know how to calculate a position like this. Why fight what my body naturally does, which is to solve this analogically? |
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| Oct-09-10 | | goldenbear: And another thing, when you calculate and fail, what does it teach you, to calculate better? When you solve this puzzle like a real human being and fail, you learn something. I prefer to start from the premise that god made a genius when he created me, and then let life prove me wrong. That way, failures come to mean something, Check out my posts on this game Kramnik vs Shirov, 2007
I can't remember missing an in-the-square idea since. |
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| Oct-12-10 | | LIFE Master AJ: I had my nth crack at winning this endgame.
http://www.chessvideos.tv/endgame-t... The position after about 55 moves was:
click for larger view
wKh4,Nc4,Pe4,f3,g2,g4/bKf7
Here - I assumed a win for White. |
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| Mar-07-12 | | LoveThatJoker: WE ARE NOW FOLLOWING
Bronstein vs Foguelman, 1960.
YOU ARE PLAYING THE ROLE OF BRONSTEIN.
Your score: 103 (par = 65)
LTJ |
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