[Event "?"]
[Site "?"]
[Date "2010.01.19"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "0-1"]
[SetUp "1"]
[FEN "8/4b3/8/p1pB4/1p3k2/1P1K2p1/P7/8 b - - 0 78"]
[PlyCount "11"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{[%evp 0,11,-126,-225,-438,-555,-853,-725,-717,-1139,-1139,-1157,-1252,-1272]} 78... c4+ $1 {A pawn sacrifice in typical style in order to open up a second front or to create a second passed pawn. This will overload the defence: Ein Bauernopfer in typischem Stil, um eine zweite Front zu eröffnen bzw. einen weiteren Freibauern zu schaffen. Dies überlastet die Verteidigung:} 79. bxc4 (79. Bxc4 g2 $19) (79. Kxc4 Ke3 80. Kb5 Kf2 81. Kxa5 g2 82. Bxg2 Kxg2 $19) (79. Kd2 c3+ 80. Kd3 c2 81. Kxc2 Ke3 $19) 79... Bc5 (79... a4 80. c5 Bxc5 $19) 80. Bc6 (80. Kc2 a4 $19) 80... a4 81. Kd2 (81. Bxa4 g2 $19) 81... a3 (81... b3 82. axb3 a3 83. Kc2 Ke3 $19) 82. Kc2 (82. Ke2 b3 83. axb3 a2 $19) 82... Ke3 83. Kb3 Kf2 0-1

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "*"]
[SetUp "1"]
[FEN "8/4k3/8/4PP2/b3K3/8/3B4/8 b - - 0 1"]
[PlyCount "3"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{Careful analysis of the following basic theoretical position will familiarize us with the characteristic ideas of such endgames. White threatens to continue e5-e6, followed by Ke5 and f5-f6. To stop this plan, Black must take the e6-square under control with his bishop. But from d7 or from b3? Let's examine both choices.} 1... Bd7 $1 {[%mdl 1]} ({On} 1... Bb3 $2 {the position is lost. First, White gives a probing check, to see which way the enemy king goes. It's important to have the bishop preventing him from getting between the pawns after e5-e6. Therefore} 2. Bg5+ $1 {Then, the White king goes to help the e-pawn from the side opposite the one the enemy king went to. For example:} ({Note that the bishop check from the other side is ineffective:} 2. Bb4+ Kf7 $1 3. Kd4 $2 Bc2 $1 4. e6+ Kf6 5. e7 Ba4 {and draws. As soon as the pawns are blocked on the same color squares as their bishop, the draw becomes obvious.}) 2... Kf7 ({Or} 2... Kd7 3. Kf4 Ba2 4. Bh4 Bf7 5. Kg5 Ke7 6. Kh6+ Kd7 7. Kg7 Bc4 8. Kf6 {and} Z0 9. e6+ {winning.}) 3. Kd4 Ba2 4. Kc5 Bb3 (4... Bb1 5. e6+ {and 6 f6.}) 5. Kd6 {and} Z0 6. e6+) 2. Bg5+ Kf7 $11 {Now Black merely waits, shuttling the bishop back and forth between c8 and d7. In order to prepare e5-e6, White needs to maneuver his king left. But this is impossible, as long as the king is tied to the defense of the f5-pawn. Which suggests a rule: The bishop must be placed where it prevents the advance of one of the pawns while simultaneously attacking the other.} *

[Event "?"]
[Site "?"]
[Date "1916.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/5k2/8/5PP1/5K2/2b5/4B3/8 w - - 0 1"]
[PlyCount "14"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{Let's look at a more complex case. Black's bishop is not ideally posted - it should be at either e7 or d8. In the basic theoretical position we started with, White won easily against such a bishop. Proceeding logically, it would seem that only one circumstance could hinder the execution of the standard winning plan, and that is the nearness of the board's edge. Let's see: "According to the rules", one should first check on h5, in order to control the g6-square. Black retreats his king to e7, forcing White's king to go on a right-hand outflanking, where there is little room to maneuver. However, White's resources for playing to win are not yet exhausted. We could decoy the king to g7 first, and then put the bishop on the e8-h5 diagonal, thus preparing a left-hand outflanking by the king.} 1. Kg4 {[%mdl 4]} (1. Bh5+ Ke7 $1 ({On} 1... Kg7 $2 2. Ke4 $18 {Black does not have the same resources to prevent a left-hand outflanking.}) 2. Kg4 Bb2 3. Bg6 {(there is no other way of making progress; but now the g6-square is not available to the king)} Bc3 4. Kh5 {(threatening 5 Kh6, 6 Bh5 etc.)} Bg7 $1 5. Bh7 Kf7 $1 6. Bg6+ Ke7 $11 {and White cannot reach his goal of preparing f5-f6+.}) ({And the bishop check on the other diagonal we already know gives nothing:} 1. Bc4+ Kg7 $1 2. Ke4 Bd2 $1 3. f6+ Kg6 $11) 1... Bb2 2. Kh5 {(Threatening 3 Kh6)} Kg7 $1 (2... Bg7 $2 {is bad because of} 3. Bc4+ Ke7 4. Kg6 $18) 3. Bb5 Bc3 4. Be8 Bd4 (4... Kf8 5. Bg6 Kg7 {is the same thing.}) 5. Bg6 ({On} 5. Kg4 {(threatening 6 Bh5, 7 Kf3, 8 Ke4 etc.) Black's king has enough time to relocate to e7:} Kf8 $1 6. Bh5 Ke7 $11 {transposing to the first variation.}) 5... Bc3 6. Kg4 {White's plan appears triumphant: 6..Kf8 7 f6 is bad; and on other moves, White plays 7 Bh5. But as J. Berger pointed out, at precisely this moment, the Black bishop succeeds in reaching its destined spot.} Ba5 $3 {With White's bishop at g6, he no longer has 7 f6+.} (6... Kf8 $2 7. f6 $18) (6... Bb4 $1) 7. Bh5 Bd8 $11 {And Black has set up the basic fortress draw of this type of ending.} 1/2-1/2

[Event "?"]
[Site "?"]
[Date "1921.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/8/3k4/8/3PP3/4K3/8/4Bb2 b - - 0 1"]
[PlyCount "13"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{Black cannot prevent White's pawns from taking one step forward: for this purpose, the bishop should have gone to c6. Therefore he must try to reach the basic drawing position with the pawns on the 5th rank (the bishop on f7 or g8, the king on d7).} 1... Bc4 $1 {[%mdl 4096]} (1... Bb5 $2 {is erroneous in view of} 2. Bb4+ $1 ({Rather than} 2. Bg3+ $2 Ke7 $1 3. d5 Be8 4. e5 Bf7 $11) 2... Ke6 (2... Kc7 3. d5 Be8 4. e5 Bf7 5. e6 $18) 3. d5+ Ke5 4. Bc3+ Kd6 5. Kd4 Be8 6. e5+ { 7.e6+-. Black misses a single tempo in all these lines.}) 2. Bg3+ Kc6 $1 ({Of course not} 2... Ke6 $2 3. Kd2 {and} Z0 4. Kc3 $18 {planning the king's march to c5. As soon as the black king leaves e6 White plays d4-d5, and the bishop fails to come to f7.}) 3. Kf4 Bg8 4. Ke5 Kd7 5. d5 Bh7 $1 {Pawns in the crosshairs: Black does not let the white king to go to f6.} ({In the meantime} 5... Bf7 6. Kf6 Ke8 $1 7. Bf4 Bg8 $11 {is less precise but still good enough for a draw.}) 6. Kf4 Bg6 7. e5 Bf7 $1 $11 1/2-1/2

[Event "?"]
[Site "?"]
[Date "1968.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "0-1"]
[SetUp "1"]
[FEN "2B5/8/3kp3/1P3pp1/3b4/7P/6K1/8 w - - 0 1"]
[PlyCount "23"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{Black's intentions are obvious: Ke5-f6 followed with e5-e4. This plan can be only parried with a king assault on d5. But prior to it White should get rid of his own b5-pawn, which only snarls his plans (positional factors are more important than pawns!).} 1. b6 $3 {[%mdl 4096]} ({I want to focus your attention to another defending possibility: a pawn sacrifice on the kingside.} 1. h4 $6 gxh4 (1... g4 $2 {seems to lead to a draw:} 2. h5 Be3 3. Kf1 f4 4. Ke2 ({Rather than} 4. h6 $2 f3 5. h7 g3 $19) ({But} 4. Kg2 $5 {is playable:} Ke5 5. h6 f3+ 6. Kg3 Bxh6 7. b6 Kf5 8. Bxe6+ $1 Kxe6 9. b7 f2 10. b8=Q $11) 4... Bd4 5. Kd3 f3 { 6...g3} 6. Bb7 Bg7 7. Be4 $1 (7. b6 $2 Kc5 8. Bxf3 gxf3 9. b7 Be5 $19) 7... Kc5 8. Ke3 Bh6+ 9. Kf2 { g3=} Bf4 (9... Kxb5 10. Kg3 $11) 10. Bc6 $11) 2. Kh3 Bf2 $5 (2... Ke5 3. Kxh4 Kf6 4. Kg3 e5 5. Bb7 Bb6 (5... e4 $2 6. Kf4 $11) 6. Kf3 Ke7) 3. b6 ({In case of} 3. Kg2 Bb6 4. Kh3 {Black can choose between} Ke5 $5 ({And} 4... Bd8 5. b6 $8 Bxb6) 5. Kxh4 Kf6 6. Kg3 e5 7. Bb7 e4 8. Kf4 Bc7+ 9. Ke3 Ke5 $19) 3... Bxb6 4. Kxh4 {Can Black win here? Frankly, I started the analysis of 1 h4 mainly to answer this question.} Ke7 $1 (4... Ke5 $2 {allows White to save the position by means of} 5. Kg5 $1 $11 { g6-f7, The same technique as in the 1 b6!! line, the king attacks the pawns from the rear!}) 5. Kg5 (5. Kg3 Kf6) 5... Kf7 $1 6. Kf4 ({If} 6. Ba6 Be3+ $1 7. Kh4 {then either} e5 $19 ({But by no means} 7... Kf6 $4 8. Kg3 e5 9. Kf3 {and} Z0 10. Bd3 $11) ({Or} 7... Bf4 $19)) 6... Kf6 7. Kf3 e5 8. Bb7 {To play e5-e4, Black must bring his king to d4, but prior to it, as we already know, he should take control over the f4-square by means of transferring his bishop to h6.} Bc5 9. Bd5 Bf8 $1 {White has two alternative defensive policies: one is waiting, another involves the king transfer to d3.} 10. Ke3 (10. Bc6 Bh6 11. Bb7 Ke7 12. Bc6 Kd6 13. Bb7 Bg5 $1 ({Notice the premature} 13... Kc5 $2 {enables White's salvation:} 14. Bc8 $1 e4+ 15. Ke2 $1 ({Rather than} 15. Kf2 $2 f4 16. Bh3 Kd4 17. Bg2 Kd3 $19) 15... f4 16. Bh3 $1 f3+ {(otherwise 17 Bg2 leads to a basic drawing position)} 17. Kf2 $11 {and there is no defense from Bh3-g4xf3.}) 14. Ba8 Kc5 15. Bb7 Kd4 $19) 10... Bh6+ 11. Kd3 Kg5 12. Bg2 {This plan is familiar to us from the previous exercise. However it fails here in view of a zugzwang.} Kf4 13. Bh3 e4+ 14. Ke2 Bf8 15. Kf2 Bc5+ 16. Ke2 Kg5 $22 ({But not} 16... Ke5 17. Bg2 f4 $4 18. Bh1 $11) 17. Bg2 Kg4 18. Kf1 Kg3 19. Bh1 Kh2 20. Bg2 Bd4 $22 $19) ({In the game, however, White failed to tackle the problem he was faced with.} 1. Kf3 $2 Ke5 $2 (1... Bb6 $1 $19 {was winning:  e5-f6, e5-e4}) 2. Bd7 $2 ({He could have saved the game with} 2. b6 $1 $11 {again.}) 2... Bb6 $1 $19 3. Ke2 Kf6 {The pawn is stopped on b5 where it blocks the important a6-f1 diagonal, so the king's march is not possible anymore:} 4. Kf3 (4. Kd3 e5 5. Kc4 e4 6. Kd5 e3) 4... e5 5. Bc6 Ke6 6. Bb7 e4+ {This gain of the bishop leads to a rapid final.} ({Black could have won in another way, too:} 6... Kd6 $5 {followed with Kc5-d4, as in the theoretical positions we have studied.}) 7. Bxe4 fxe4+ 8. Kxe4 Bf2 (8... Bc7 9. b6 Bb8 $1 (9... Bxb6 $4 10. h4 $1 $11) 10. Kf3 (10. h4 g4 $19) 10... Kf5 11. Ke3 Kg6 12. Kf3 Kh5 $19 {is equivalent.}) 9. b6 Kd6 10. Kf5 Bh4 {White resigned.}) 1... Bxb6 ({Attempting to save a tempo by ignoring the b6-pawn fails: if} 1... Ke5 $5 {then the simplest is} 2. Kf3 $5 ({But} 2. b7 Ba7 3. Kf3 (3. h4 $2 gxh4 4. Kh3 Kf6 5. Kxh4 e5 6. Kg3 e4 7. Kf4 Bb8+ 8. Ke3 Ke5 9. Ke2 f4 10. Bg4 Ba7 11. Bh5 Kf5 $19) 3... Kf6 4. Ke2 (4. Bd7 e5 $19) 4... e5 5. b8=Q $3 Bxb8 6. Kd3 e4+ 7. Kd4 $11 {is also playable.}) 2... Kf6 3. Ke2 e5 4. Kd3 Bxb6 5. Kc4 e4 6. Kd5 $11) 2. Kf3 Ke5 3. Ke2 $1 Kf6 4. Kd3 e5 5. Kc4 e4 6. Kd5 e3 ({In case of} 6... Kg6 {(with the idea 7...e3 8 Ba6 Kh5), both} 7. Kc4 ({And} 7. Ke5 Bc7+ 8. Kd4 $11) 7... f4 8. Kd5 $1 e3 9. Bg4 $11 {are good.}) 7. Ba6 {The draw is obvious now.} g4 $5 (7... Kg6 8. Be2 $11) 8. hxg4 fxg4 9. Ke4 (9. Bf1 $4 g3 $19) 9... Kg5 10. Kd3 $1 { e2-f1, b7} Kh4 11. Ke2 Kg3 12. Bc8 $11 ({Or} 12. Kf1 Kh2 13. Bb7 $11) 0-1

[Event "?"]
[Site "?"]
[Date "1887.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/2k1b3/2P5/3K1P1B/8/8/8/8 w - - 0 1"]
[PlyCount "13"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{With separated passed pawns, the stronger side's strategy is always one and the same: the king goes toward the pawn that the bishop is holding back.} 1. Bf3 {[%mdl 1]} Kd8 2. Ke6 Bb4 3. f6 Ba5 4. f7 Bb4 5. Kf6 Bc3+ 6. Kg6 Bb4 7. Kg7 $18 1-0

[Event "?"]
[Site "?"]
[Date "1950.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/2bB4/2P5/6k1/4K3/5P2/8/8 w - - 0 1"]
[PlyCount "8"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{The next diagram offers a very simple example. The draw is obvious:} 1. Kd5 {[%mdl 1] is met by} Kf6 {if the king goes to b7, Black's king turns up at d8. Black can draw in large part because his bishop restrains both pawns along the b8-h2 diagonal.} 2. Kc5 Ke7 3. Kb5 Bg3 4. Kb6 Kd8 $11 1/2-1/2

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Opposite Colored Bishop Endgames"]
[Black "Opposite Colored Bishop Endgames"]
[Result "1/2-1/2"]
[SetUp "1"]
[FEN "8/1k3p2/1P3Kp1/7p/2b2P2/4B1P1/7P/8 w - - 0 1"]
[PlyCount "6"]
[SourceVersion "1"]
[SourceVersionDate "2010.03.17"]
[SourceQuality "1"]

{In such situations the bishop can easily handle the defense of the kingside, so a drawn outcome should come as no surprise.} 1. f5 {[%mdl 1] (the only try)} gxf5 $6 {This move makes Black's task a bit more difficult.} (1... Bd3 $1 $11 {is safer.}) 2. Kxf5 Be6+ $1 ({The assessment of the position would change if Black incautiously played:} 2... Kc6 $2 3. Kg5 Be2 4. h3 $1 ({But not} 4. Kf6 Bc4 5. h3 $2 {in view of} Bf1 $1 6. g4 h4 $1 7. Kxf7 Bxh3 8. g5 Bf1 $11 {the advance of the h-pawn distracts the bishop from the defense of the b6-pawn.}) 4... Kb7 (4... Bf1 5. g4 hxg4 6. h4 $18) 5. Bd4 Kc6 6. g4 hxg4 7. h4 $18 {White has achieved his aim: the creation of a second passed pawn!} g3 8. Kf4 $1 (8. h5 f6+ 9. Kg6 $6 {is much less convincing:} ({White's play might be strengthened, however, by} 9. Kh4 $1) 9... f5 10. h6 f4 11. Kg5 f3 12. h7 f2) 8... Bh5 (8... g2 9. Kg5 $18 { h5}) 9. Kxg3 f6 10. Kf4 Bg6 11. Kg4 Kb7 12. h5 Bh7 {Black has set up a barrier, but one which can be overcome without much difficulty. White's king goes to a5, to free his bishop from the defense of the b6-pawn. The f6-pawn will then have to advance, and White's king will return to the kingside.}) 3. Kg5 Bg4 $11 1/2-1/2