Answers.Body: <blockquote>
  <p>What is the blacks plan to keep this a draw - and how does it follow from that that Bd8 loses?</p>
  </blockquote>
  <p>Short answer: Your bishop has to be able to guard the e1-a5 and g1-a7 diagonals. Bd8 gives up on that and so gives up on the draw.</p>
  <p>Long answer: If this were a simple endgame where white had the king and a pawn against black's king then white would need to get the king to either b6 or b7 to win. Something similar applies here. That's where the black bishop controlling the g1-a7 diagonal comes in. If the white king goes to b6 it can be driven away by the bishop. The black king will also have to come to c7 at some stage to keep the white king out of b7.</p>
  <p>While the pawn remains on a4 you keep your bishop on the e1-a5 diagonal. Then the pawn can only move to a5 with the king's help. If that happens then switch to the g1-a7 diagonal. The black king and bishop can then combine to prevent further progress.</p>
  <p>Here's what that looks like:</p>
  <pre><code>[FEN &quot;2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1&quot;]
  
  1... Bd2 2. a5 Kc7 {must stop the white king getting to b7} 3. Be6 {the bishop must cover the g4 square to stop the black pawn from queening} Be3 {Now switch diagonals to stop further white progress} 4. a6 Kd6 {and the bishop stops any more progress with either king or pawn}
  </code></pre>
  <p>So what happens if white has the idea of sacrificing the d pawn to make a path for the white king? Obviously white will have to move the bishop to f5 rather than e6, but what then? Well then the black bishop must be prepared to sacrifice itself for the pawn when it gets to a7. Meanwhile the black king will come round and force the white bishop to take the passed g pawn allowing the black king to take the last remaining white pawn - draw.</p>
  <p>Let's see that:</p>
  <pre><code>[FEN &quot;2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1&quot;]
  
  1... Bd2 2. a5 Kc7 3. Bf5 Be3 4. Ka6 {Trying to get to b7} Bd4 {waiting} 5. d6+ {deflecting the king} Kxd6 6. Kb7 {Success!} Kc5 7. a6 Kc4 8. a7 Bxa7 9. Kxa7 Kd3 10. Kb6 g4 11. Kc5 g3 12. Bh3 Kxe4
  </code></pre>
  <p>Finally, what iof white is patient and tries to get the king further up the board to help the a pawn get through? Again the bishop has to be ready to switch diagonals and drive the king away from b6.</p>
  <pre><code>[FEN &quot;2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1&quot;]
  
  1... Bd2 2. Kb6 Be3+ 3. Ka6 Bd2 4. a5 Kc5 5. Bf5 Bb4 {and white can't make further progress} 
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-08-24T15:09:33.893Z
Answers.Text: Thank you! Now I see: blacks goal is to stop the a-pawn without having to sacrifice the bishop for nothing. And that can't be achieved once the white king can advance to b7 and the a-pawn to a6. The black king can help guard b7 and if it is distracted by the d-pawn advancing then black CAN sacrifice their bishop (this part is really hard to see OTB).  There is one rather crucial position you didn't show in this regard where the black bishop *cannot* go to the g1-a7 diagonal despite the white pawn already having advanced to a5. But the idea there is the same.
Answers.UserDisplayName: Carlo Wood
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-08-23T22:09:49.060Z
Answers.LastActivityDate: 2024-08-23T22:09:49.060Z
Answers.UserDisplayName: Brian Towers
Answers.Body: <p>Since you say that the computer analysis is over your head, there may be something very subtle involved, and indeed the position is quite complex. I will not try to analyze it here, but there is a simple consideration concerning opposite-Bishop endgames that might help you to make sense of the computer analysis you already have. Both players already have dangerous passed pawns. To promote, those pawns must pass over squares of the same color as the enemy Bishop, which they can only do with the support of their King. Play in these endings often involves a fight for control of these squares, which are a5 and a7 for the White a-pawn. There is not much you can do about a5, so a7 will be the key, and you need to get your Bishop onto that diagonal ASAP. Short answer, ..Bd8 is not a good start. It is important to place your Bishop where it has as much mobility as possible</p>
  <p>Longer answer. Did you consider ..Kc7? If I have got it right, Kxa5, Kxc8
  is at least draw for you (but only because you promote with check in the line Kb6 g4; a5 g3; a6 Kb8; a7+ Ka8; d6 g2; d7 g1=Q+) so White would not take your bishop but retreat their own, when you have gained a tempo to play Bb6 getting your Bishop efficiently onto the correct diagonal.</p>
  <p>I hope this helps. If not, perhaps you should share the analysis that baffles you.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-08-23T17:14:23.063Z
Answers.LastActivityDate: 2024-08-23T17:14:23.063Z
Answers.UserDisplayName: Philip Roe
Body: <p>I ran into the following position while playing a game.</p>
  <pre><code>[Title &quot;Black to move and draw?&quot;]
  [StartFlipped &quot;0&quot;]
  [FEN &quot;2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1&quot;]
  </code></pre>
  <p>In this drawn position, I played as black Bd8, which results in a lost position.</p>
  <p>Of course I can, and did, analyse this position with a computer, but it is completely over my head. Surely a Grand Master would have some insight, a plan, a system - that would make it relatively easy to keep this position a draw with black?</p>
  <p>What is the blacks plan to keep this a draw - and how does it follow from that that Bd8 loses?</p>
  
Tags: <strategy><draw><bishop-endgame>
Title: Can someone explain this unequal bishops position?
ThreadText: # Can someone explain this unequal bishops position?
  
  (Asked by: username_0 on 2024-08-23)
  
  I ran into the following position while playing a game.
  
  ```
  [Title "Black to move and draw?"]
  [StartFlipped "0"]
  [FEN "2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1"]
  
  ```
  
  In this drawn position, I played as black Bd8, which results in a lost position.
  
  Of course I can, and did, analyse this position with a computer, but it is completely over my head. Surely a Grand Master would have some insight, a plan, a system - that would make it relatively easy to keep this position a draw with black?
  
  What is the blacks plan to keep this a draw - and how does it follow from that that Bd8 loses?
  
  **Tags:** strategy, draw, bishop-endgame
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2024-08-23. Score: 2
  
  > What is the blacks plan to keep this a draw - and how does it follow from that that Bd8 loses?
  
  Short answer: Your bishop has to be able to guard the e1-a5 and g1-a7 diagonals. Bd8 gives up on that and so gives up on the draw.
  
  Long answer: If this were a simple endgame where white had the king and a pawn against black's king then white would need to get the king to either b6 or b7 to win. Something similar applies here. That's where the black bishop controlling the g1-a7 diagonal comes in. If the white king goes to b6 it can be driven away by the bishop. The black king will also have to come to c7 at some stage to keep the white king out of b7.
  
  While the pawn remains on a4 you keep your bishop on the e1-a5 diagonal. Then the pawn can only move to a5 with the king's help. If that happens then switch to the g1-a7 diagonal. The black king and bishop can then combine to prevent further progress.
  
  Here's what that looks like:
  
  ```
  [FEN "2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1"]
  
  1... Bd2 2. a5 Kc7 {must stop the white king getting to b7} 3. Be6 {the bishop must cover the g4 square to stop the black pawn from queening} Be3 {Now switch diagonals to stop further white progress} 4. a6 Kd6 {and the bishop stops any more progress with either king or pawn}
  
  ```
  
  So what happens if white has the idea of sacrificing the d pawn to make a path for the white king? Obviously white will have to move the bishop to f5 rather than e6, but what then? Well then the black bishop must be prepared to sacrifice itself for the pawn when it gets to a7. Meanwhile the black king will come round and force the white bishop to take the passed g pawn allowing the black king to take the last remaining white pawn - draw.
  
  Let's see that:
  
  ```
  [FEN "2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1"]
  
  1... Bd2 2. a5 Kc7 3. Bf5 Be3 4. Ka6 {Trying to get to b7} Bd4 {waiting} 5. d6+ {deflecting the king} Kxd6 6. Kb7 {Success!} Kc5 7. a6 Kc4 8. a7 Bxa7 9. Kxa7 Kd3 10. Kb6 g4 11. Kc5 g3 12. Bh3 Kxe4
  
  ```
  
  Finally, what iof white is patient and tries to get the king further up the board to help the a pawn get through? Again the bishop has to be ready to switch diagonals and drive the king away from b6.
  
  ```
  [FEN "2B5/8/3k4/bK1Pp1p1/P3P3/8/8/8 b - - 1 1"]
  
  1... Bd2 2. Kb6 Be3+ 3. Ka6 Bd2 4. a5 Kc5 5. Bf5 Bb4 {and white can't make further progress} 
  
  ```
  
  > **Comments:**
  > **username_0**: Thank you! Now I see: blacks goal is to stop the a-pawn without having to sacrifice the bishop for nothing. And that can't be achieved once the white king can advance to b7 and the a-pawn to a6. The black king can help guard b7 and if it is distracted by the d-pawn advancing then black CAN sacrifice their bishop (this part is really hard to see OTB).  There is one rather crucial position you didn't show in this regard where the black bishop *cannot* go to the g1-a7 diagonal despite the white pawn already having advanced to a5. But the idea there is the same.  
  
  ---
  
  ### Answer by username_2 on 2024-08-23. Score: 0
  
  Since you say that the computer analysis is over your head, there may be something very subtle involved, and indeed the position is quite complex. I will not try to analyze it here, but there is a simple consideration concerning opposite-Bishop endgames that might help you to make sense of the computer analysis you already have. Both players already have dangerous passed pawns. To promote, those pawns must pass over squares of the same color as the enemy Bishop, which they can only do with the support of their King. Play in these endings often involves a fight for control of these squares, which are a5 and a7 for the White a-pawn. There is not much you can do about a5, so a7 will be the key, and you need to get your Bishop onto that diagonal ASAP. Short answer, ..Bd8 is not a good start. It is important to place your Bishop where it has as much mobility as possible
  
  Longer answer. Did you consider ..Kc7? If I have got it right, Kxa5, Kxc8
  is at least draw for you (but only because you promote with check in the line Kb6 g4; a5 g3; a6 Kb8; a7+ Ka8; d6 g2; d7 g1=Q+) so White would not take your bishop but retreat their own, when you have gained a tempo to play Bb6 getting your Bishop efficiently onto the correct diagonal.
  
  I hope this helps. If not, perhaps you should share the analysis that baffles you.
  
  
  ---
  
  