Answers.Body: <p>It's because <code>1. exf8=Q+ Kxh7 2. Rxd7??</code> would be stalemate. I think it is a even a theoretical draw after <code>1. exf8=Q+ Kxh7 2. Qg7+</code>. Therefore <code>1. exf8=B+!</code> (with check!) is better, since white then can keep an extra piece and win easily.</p>
  
  <pre><code>[FEN "5r2/3qPbkB/8/7P/8/8/8/1K1R4 w - - 0 1"]
  
  1. exf8=Q+ (1. exf8=B+!) Kxh7 2. Rxd7? (2. Qg7+)
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-06-18T15:11:38.137Z
Answers.Text: Indeed, after 1.exf8Q+ Kxh7 2.Qg7+, it's a draw, according to the tablebases. It's the famous endgame R+p vs. B where white would be winning with a pawn on h2, h3 or h4, but not on h5!
Answers.UserDisplayName: Maxwell86
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-06-18T15:13:57.147Z
Answers.Text: @Maxwell86 This endgame has also been discussed in an earlier question http://chess.stackexchange.com/questions/2801
Answers.UserDisplayName: Dag Oskar Madsen
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-06-19T06:34:51.493Z
Answers.Text: I don't want to seem dumb but what's wrong with kx(whatever is on f8)? I don't see how it varies either, because a queen can do all the bishop can!
Answers.UserDisplayName: Alec Teal
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-06-19T08:06:54.167Z
Answers.Text: After 1.exf8=Q+ Kxf8 2.Rxd7 black is simply lost, that's what's wrong with it.
Answers.UserDisplayName: RemcoGerlich
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-06-18T14:22:00.320Z
Answers.LastActivityDate: 2015-06-18T18:47:02.890Z
Answers.LastEditDate: 2015-06-18T18:47:02.890Z
Answers.UserDisplayName: Dag Oskar Madsen
Body: <p>Why does Fritz prefer underpromotion in this position? How can underpromotion to bishop evaluate so much higher than normal queen promotion?</p>
  
  <p>Can this be a bug in the Fritz 14 chess engine?</p>
  
  <p><img src="https://i.sstatic.net/0O8db.png" alt="Strange evaluation"></p>
  
Tags: <engines><evaluation><pawn-promotion><fritz>
Title: Why does Fritz prefer underpromotion in this position?
ThreadText: # Why does Fritz prefer underpromotion in this position?
  
  (Asked by: username_0 on 2015-06-18)
  
  Why does Fritz prefer underpromotion in this position? How can underpromotion to bishop evaluate so much higher than normal queen promotion?
  
  Can this be a bug in the Fritz 14 chess engine?
  
  ![Strange evaluation](https://i.sstatic.net/0O8db.png)
  
  **Tags:** engines, evaluation, pawn-promotion, fritz
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-06-18. Score: 23 | Accepted answer
  
  It's because `1. exf8=Q+ Kxh7 2. Rxd7??` would be stalemate. I think it is a even a theoretical draw after `1. exf8=Q+ Kxh7 2. Qg7+`. Therefore `1. exf8=B+!` (with check!) is better, since white then can keep an extra piece and win easily.
  
  ```
  [FEN "5r2/3qPbkB/8/7P/8/8/8/1K1R4 w - - 0 1"]
  
  1. exf8=Q+ (1. exf8=B+!) Kxh7 2. Rxd7? (2. Qg7+)
  
  ```
  
  > **Comments:**
  > **username_2**: Indeed, after 1.exf8Q+ Kxh7 2.Qg7+, it's a draw, according to the tablebases. It's the famous endgame R+p vs. B where white would be winning with a pawn on h2, h3 or h4, but not on h5!  
  > **username_1**: @username_2 This endgame has also been discussed in an earlier question http://chess.stackexchange.com/questions/2801  
  > **username_3**: I don't want to seem dumb but what's wrong with kx(whatever is on f8)? I don't see how it varies either, because a queen can do all the bishop can!  
  > **username_4**: After 1.exf8=Q+ Kxf8 2.Rxd7 black is simply lost, that's what's wrong with it.  
  
  ---
  
  