Answers.Body: <p>Easy. Exchange BOTH pairs of light officers (BxN, then NxB) and you have an almost trivial won pure king/pawn endgame. General Principle: If you are material up in the endgame, exchange officers. If down, pawns. (As usual, exceptions abound.)</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-06-21T05:46:06.050Z
Answers.LastActivityDate: 2023-06-21T05:46:06.050Z
Answers.UserDisplayName: Hauke Reddmann
Answers.Body: <p>After Kf5 white replies with Nc4 and the only way to avoid losing the a pawn is to play the knight back to the poor square b7 and it is very difficult to see how black can make progress. If the knights are ever exchanged then the position becomes a trivially drawn opposite coloured bishop endgame.</p>
  <pre><code>[fen &quot;8/5p2/4pkpp/p1n5/Pp6/1Bb1PP2/2PNK2P/8 b - - 0 1&quot;]
  
  1...Kf5 2. Nc4 Nb7
  </code></pre>
  <p>On the other hand, if black exchanges off the bishop for the knight by Bxd2 then black is left with a good knight versus a bad bishop with a potential distant passed pawn on the king side. (Note that if the white bishop moves then that immediately loses the a pawn.) Black will play moves like g5, Ke5, f5, g4.</p>
  <p>Endgames are all about calculation and so black should also calculate carefully what happens if the other minor piece is also exchanged by Nxb3. This opens up the route for white to play a sequence of moves like Kd3-c4-b5, Kxa5 and queen the a pawn. Can white win via this route? The answer is not quite. With correct play black queens the h pawn one move before white can queen the a pawn and as they are on the same diagonal black's queen covers a8.</p>
  <pre><code>[fen &quot;8/5p2/4pkpp/p1n5/Pp6/1Bb1PP2/2PNK2P/8 b - - 0 1&quot;]
  
  1...Bxd2 2. Kxd2 Nxb3 3. cxb3 Ke5 4. Kd3 f5 5. Kc4 g5 6. Kb5 g4 7. fxg4 fxg4 8. Kxa5 h5 9. Kxb4 h4 10. a5 g3 11. hxg3 h3! (11...hxg3? {only draws}) 12. a6 h2 13. a7 h1=Q
  </code></pre>
  <blockquote>
  <p>Is there a useful principle to learn from this?</p>
  </blockquote>
  <p>Calculation is key in endgames. If you watch the top players they don't rush in and play the obvious move when they think they have a winning endgame. They take the time to calculate the position through to the win and only then play the move.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-06-23T14:25:07.847Z
Answers.Text: 4...Kd5 seems safer than going for the pawn race.
Answers.UserDisplayName: eyeballfrog
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-06-25T09:17:10.817Z
Answers.Text: Instead of 7 fxg4 white could play f4+ and very likely getting the queen first then getting to more complicated endgame (black king would probably go Kf6, otherwise (Ke4) white will get queen with check.
Answers.UserDisplayName: Adam Tucholski
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-06-25T14:55:20.500Z
Answers.Text: @AdamTucholski No. After 7. f4+ Kd5 8. Kxa5 Kc5 9. Ka6 Kc6 the white king is never going to succeed in getting out of the way of the a pawn and black is going to queen and win.
Answers.UserDisplayName: Brian Towers
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-06-21T10:11:27.907Z
Answers.LastActivityDate: 2023-06-21T15:44:11.007Z
Answers.LastEditDate: 2023-06-21T15:44:11.007Z
Answers.UserDisplayName: Brian Towers
Body: <p>In this position, Stockfish gives black (me) -8.1 and recommends BxN.</p>
  <pre><code>8/5p2/4pkpp/p1n5/Pp6/1Bb1PP2/2PNK2P/8 b - - 7 28
  </code></pre>
  <p>Instead I played Kf5 and the evaluation plummets to -2.1.</p>
  <p>My understanding was that generally bishops are preferred over knights in endgames, so I'm trying to understand what is different about this position. Looking at Stockfish's line, it looks like somehow this is useful for dragging the king away from protecting the pawn on H2, which Black's king then goes after.</p>
  <p>Is there a useful principle to learn from this?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-06-28T15:29:44.770Z
Comments.Text: When analyzing with an engine, don't just stick to the next move. In the alternative Bxd2, the engine wants to trade every piece on the board to get a winning pawn endgame.
Comments.UserDisplayName: David
Tags: <endgame><strategy><knights><bishops>
Title: Why exchange bishop for knight in this endgame?
ThreadText: # Why exchange bishop for knight in this endgame?
  
  (Asked by: username_0 on 2023-06-21)
  
  In this position, Stockfish gives black (me) -8.1 and recommends BxN.
  
  ```
  8/5p2/4pkpp/p1n5/Pp6/1Bb1PP2/2PNK2P/8 b - - 7 28
  
  ```
  
  Instead I played Kf5 and the evaluation plummets to -2.1.
  
  My understanding was that generally bishops are preferred over knights in endgames, so I'm trying to understand what is different about this position. Looking at Stockfish's line, it looks like somehow this is useful for dragging the king away from protecting the pawn on H2, which Black's king then goes after.
  
  Is there a useful principle to learn from this?
  
  **Tags:** endgame, strategy, knights, bishops
  
  > **Comments:**
  > **username_1**: When analyzing with an engine, don't just stick to the next move. In the alternative Bxd2, the engine wants to trade every piece on the board to get a winning pawn endgame.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2023-06-21. Score: 12
  
  Easy. Exchange BOTH pairs of light officers (BxN, then NxB) and you have an almost trivial won pure king/pawn endgame. General Principle: If you are material up in the endgame, exchange officers. If down, pawns. (As usual, exceptions abound.)
  
  
  ---
  
  ### Answer by username_3 on 2023-06-21. Score: 12
  
  After Kf5 white replies with Nc4 and the only way to avoid losing the a pawn is to play the knight back to the poor square b7 and it is very difficult to see how black can make progress. If the knights are ever exchanged then the position becomes a trivially drawn opposite coloured bishop endgame.
  
  ```
  [fen "8/5p2/4pkpp/p1n5/Pp6/1Bb1PP2/2PNK2P/8 b - - 0 1"]
  
  1...Kf5 2. Nc4 Nb7
  
  ```
  
  On the other hand, if black exchanges off the bishop for the knight by Bxd2 then black is left with a good knight versus a bad bishop with a potential distant passed pawn on the king side. (Note that if the white bishop moves then that immediately loses the a pawn.) Black will play moves like g5, Ke5, f5, g4.
  
  Endgames are all about calculation and so black should also calculate carefully what happens if the other minor piece is also exchanged by Nxb3. This opens up the route for white to play a sequence of moves like Kd3-c4-b5, Kxa5 and queen the a pawn. Can white win via this route? The answer is not quite. With correct play black queens the h pawn one move before white can queen the a pawn and as they are on the same diagonal black's queen covers a8.
  
  ```
  [fen "8/5p2/4pkpp/p1n5/Pp6/1Bb1PP2/2PNK2P/8 b - - 0 1"]
  
  1...Bxd2 2. Kxd2 Nxb3 3. cxb3 Ke5 4. Kd3 f5 5. Kc4 g5 6. Kb5 g4 7. fxg4 fxg4 8. Kxa5 h5 9. Kxb4 h4 10. a5 g3 11. hxg3 h3! (11...hxg3? {only draws}) 12. a6 h2 13. a7 h1=Q
  
  ```
  
  > Is there a useful principle to learn from this?
  
  Calculation is key in endgames. If you watch the top players they don't rush in and play the obvious move when they think they have a winning endgame. They take the time to calculate the position through to the win and only then play the move.
  
  > **Comments:**
  > **username_4**: 4...Kd5 seems safer than going for the pawn race.  
  > **username_5**: Instead of 7 fxg4 white could play f4+ and very likely getting the queen first then getting to more complicated endgame (black king would probably go Kf6, otherwise (Ke4) white will get queen with check.  
  > **username_3**: @username_5 No. After 7. f4+ Kd5 8. Kxa5 Kc5 9. Ka6 Kc6 the white king is never going to succeed in getting out of the way of the a pawn and black is going to queen and win.  
  
  ---
  
  