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| Aug-21-10 | | David2009: 
click for larger view Julio Bolbochan vs C H Maderna, 1953 White 52? Without the two a Pawns, this position is a difficult book win starting 52 f7! (not of course fxe7?? drawn since the BK can occupy g7 and h8 from which he cannot
be driven away: White wins the a6 Pawn which does him no good at all). The a Pawns make it slightly easier. I have set the position upon Crafty before consulting the game and won without difficulty starting f7: I suspect that Crafty for once does not find the toughest defence.
Crafty link: http://www.chessvideos.tv/endgame-t... Time to check other kibitzer's views.
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Aug-21-10
 | | scormus: And the winning move is ....... wibble! Yes, nice find <Once> BTW Nice new avatar as well, reminds me of Victor Vasarely. |
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| Aug-21-10 | | sethoflagos: 52 f7 ... an impregnable 7th rank pawn is definitely worth more than a mere bishop! The first plan that comes to mind is to get WK to g8 and then WB to g7 where it can chase BB off the a3-f8 diagonal. P-QR4 is available as a zwischenzug to break a blockade on f8 if necessary. Basic continuations I saw were:
52..Kf6 53 Kg7 Bc5 54 Kg8 Bd6 55 Bg7 Bc5 56 Bf8 Be3 57 Ba3 Bh6 58 Bc8 52..Bf8 53 Kh7 Ke7 54 Kg8 Bh6 55 Bg7 |
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| Aug-21-10 | | sethoflagos: LOL <once> obviously when I said 'zwischenzug' I really meant 'wibble'! |
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| Aug-21-10 | | kevin86: Obviously white couldn't take the bishop as his bishop is of the wrong color and doesn't cover a8,the queening square for the pawn. Instead he must use his own bishop the chase the adverse bishop from the queening square. A typical B+P vs bishop ending...the other pawns are a decoy. |
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| Aug-21-10 | | Once: <scormus: reminds me of Victor Vasarely.> Very cultured! And to think I chose it because it reminded me of the decor of the sickbay in the USS Voyager :-) |
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| Aug-21-10 | | Patriot: Practically speaking, 52.f7 is the move and nothing else is required. You don't have to figure out what happens after that because it's 52.f7 or draw! But as a puzzle, it doesn't hurt to look a little further for the sake of board vision practice. I figured either 52...Ke6 or 52...Bf8 was best to consider. 52...Ke6 53.Kg7 Bd6/Bc5/Ba3 54.Kg8 with 55.Bg7 and 55.Bf8 coming up. 52...Bf8 53.Kh7 Ke7? 54.Kg8 with 55.Bb4+ threatened. 53...Ke6 54.Kg8 is similar to above. I wasn't sure how white was going to prevent the bishop from capturing after pawn promotion. So in that regard the game is instructive. Forcing the black bishop on the h6-f8 diagonal, and interposing the white bishop at g7 was key. I probably should have tried to calculate it to a win, but it felt like a waste of time. |
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Aug-21-10
 | | al wazir: And if 57...Bd4, then 58. Be7! |
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Aug-21-10
 | | Jimfromprovidence: I liked the clever 47 b5!
click for larger viewNotice that black cannot play 47...axb5 because the king or bishop has to move to prevent the bishop skewer. |
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Aug-21-10
 | | OBIT: For this position, you can pretend the two a-pawns do not exist, in which case this becomes a standard B+P vs B win. In fact, the position is essentiallly identical to #176 in Fine's "Basic Chess Endings," except the position in Fine's book has the Black king on g6. 
click for larger viewWith the king on g6, 59. Bc3! still wins the game immediately, putting Black in zugzwang. Fine misses this shortcut, giving as the solution 59. Bd2 Bg7 60. Bd3 Kf6 61. Bd4+. |
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| Aug-21-10 | | ZUGZWANG67: <<Patriot>: Practically speaking, 52.f7 is the move and nothing else is required. You don't have to figure out what happens after that because it's 52.f7 or draw!> Well, I think it depends whether one considers the win obvious <because> of the shortness of the f8/h6 diagonal. 52.f7 Ke6 (Here I thought mistakenly that 52...Bf8 was forced. In fact, 52...Ke6 is more to the point although unsufficient) 53.Kg7 Kf5 54.Kg8 Kg6. 
click for larger viewThis is what we've been taught as one of the defensive stances for the weaker side: the weak K opposed to the strong one. But here there's still a forced win. That is because the f8/h6 diagonal has less than 4 squares. By kicking off the BB from the longer diagonal that crosses the promotion square and then, doing the same <or> interfering on the short one, W ensures promotion: 55.Bg7 Bb4 56.Bf8 Bd2 57.Ba3 Bh6 58.Bb2!
click for larger viewThe point. The BB doesn't have anywhere to go and the BK can't land to g5: 58...Kg5 59.Bc1+. But either 58...a5 or 58...Kf5 provokes 59.Bg7. This is the interfering device. Now consider this:
click for larger viewIt's easy to see that there's no more win. It is so because the BB always has an spare square at his disposal along the critical diagonal. Only when one is aware of those 2 scenarios should one condider having solved after merely 52.f7. Well, this is my opinion.
Peace! |
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| Aug-21-10 | | sethoflagos: <Patriot: .... Forcing the black bishop on the h6-f8 diagonal, and interposing the white bishop at g7 was key.> Does this only work for white because the h6-f8 diagonal is short enough for K&B to control without occupation? I can't see a win from this similar position 
click for larger view |
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| Aug-21-10 | | ZUGZWANG67: <<sethoflagos>: Does this only work for white because the h6-f8 diagonal is short enough for K&B to control without occupation? I can't see a win from this similar position.> That's the key to such an endgame. Centurini discovered that in the very vast majority of cases it is a draw when the shorter diagonal is more than 3 square long. See my previous post. |
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| Aug-21-10 | | SamAtoms1980: 52 f7 was clear. My general plan from there consisted of the following: (a) King to g8; (b) Bishop to f8, driving the black bishop to h6; (c) Bf8-b4-d2. I don't know if it was necessary to play pawn to a4. |
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| Aug-21-10 | | Marmot PFL: This actually seems like a fairly simple theoretical position. The winning plan is 1) advance the pawn to f7 (obvious) 2) bring the king to g8 3) use the threat to exchange bishops to drive black from the queening square. For example 52 f7 Ke6 (Bf8 53 Kh7 and Kg8) 53 Kg7 Bd6 54 Kg8 Be7 55 Bg7 Bd6 56 Bf8 Bf4 57 Bb4 Bh6 58 Bc3 and Bg7 winning |
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| Aug-21-10 | | Patriot: <<ZUGZWANG67>: <<Patriot>: Practically speaking, 52.f7 is the move and nothing else is required. You don't have to figure out what happens after that because it's 52.f7 or draw!>
Well, I think it depends whether one considers the win obvious <because> of the shortness of the f8/h6 diagonal.> When I said "practically speaking", I'm referring to OTB logic. Anything other than 52.f7 draws, thanks to 52...Bxf6. White's only attempt to win is 52.f7, therefore he can just play the move and see what happens. Calculating further at this point during a game to see if a win is there is a waste of time. It's not necessary to see the key win--either play 52.f7 or allow your opponent to play 52...Bxf6 and accept a draw...it's as simple as that. Your diagrams are very instructive. In your second diagram, you said <The point. The BB doesn't have anywhere to go and the BK can't land to g5: 58...Kg5 59.Bc1+. But either 58...a5 or 58...Kf5 provokes 59.Bg7. This is the interfering device.> After 58...a5 59.a4 is winning not 59.Bg7, which I'm sure is just a typo. The last diagram is a really good illustration of a draw. |
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| Aug-21-10 | | VincentL: "Very difficult"
I think the solution here is:
(1) 52. f7
(2) Get the white king to g8
(3) Get the white bishop to f8.
This will force the black bishop off the a3-f8 diagonal. The black king will not be able to
get to e8 or e7, as these will be protected by the white pawn and bishop respectively.
(4) Exchange bishops or play Be7 (once the black bishop is off the a3 f8 diagonal)
(5) Queen the f pawn and win.
I don't have time to write up variations - let us see how this went. |
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| Aug-21-10 | | VincentL: Well, black had a neat resource at the end (....Bh6) but it seems my approach was largely correct. |
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| Aug-21-10 | | DarthStapler: I got the first move |
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Aug-21-10
| | Jimfromprovidence: Based on the content of the posting of <dzechiel>, the following position is a table base win for white, with white to play.
click for larger viewAny takers? In order to win you need to keep the black king away from the queening square as you go about capturing black's pawn. Any one interested in the solution should click on the link below. http://www.k4it.de/index.php?topic=... |
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| Aug-21-10 | | watwinc: The first move is obviously f7, and after that I dimly remembered the rule from the Averbakh book on minor piece endings that Black loses if there are only three squares for the bishop on the short diagonal ... |
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| Aug-21-10 | | BOSTER: Using the schematic thinking white can build such pos. Kg8, Ba3 and pawn on f7.
The Bishop moves on diagonal a3-f8 through c3-g7-f8. When White Bishop on f8, black can try moving his Bishop on diagonal c1-h6 to keep white pawn from h6, but after Bc1 game is over. |
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| Aug-21-10 | | rapidcitychess: 52.f7 is the solution to an easy Saturday puzzle. |
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| Aug-21-10 | | TheBish: Julio Bolbochan vs C H Maderna, 1953 White to play (52.?) "Very Difficult"
I realized right away what the first move was, since 52. fxe7? Kxe7 would lead to a wrong-colored bishop endgame (doesn't control the a8 queening square), with Black's a-pawn not changing that outcome. Therefore... 52. f7! and White will win after some maneuvering to trade off bishops. No time left to illustrate what must have already been shown, so I'll leave it at that and check out Sunday's now... |
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| Aug-22-10 | | CHESSTTCAMPS: Finally, some time to work on a puzzle this week. White's play must be directed by essential endgame knowledge: with white in possession of the "wrong" bishop, white's a-pawn can't be promoted against best defense unless the BK can be denied access to a8 or white's a-pawn can be converted to a b-pawn by a forced exchange. Neither of these possibilities exists; therefore, white must promote the f-pawn to win. Fortunately, this can be accomplished by a maneuver that is very useful in some same-colored bishop endings: 52.f7
Necessary to preserve winning chances. Now white can get the K to g8 and force an exchange of bishops against any defense. A. 52... Kd6 53.Kg7 B a3-diagonal 54.Kg8 B a3-diagonal 55.Bg7 B a3-diagonal 56.Bf8 B c1-diagonal 57.B a3-diagonal (not en prise) Bh6 58.B a1-diagonal followed by 59.Bg7 wins. B. 52... Bf8 53.Kh7 followed by 54.Kg8 followed by the same maneuver wins. |
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