Answers.Body: <p>My instance of Stockfish 16 saw M11 after about 7 seconds, so I think you just didn't wait long enough, although Stockfish 16 is stronger than 14 so that could also be why.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-07-24T02:20:25.583Z
Answers.Text: Indeed that makes sense. Curious, at what search depth did it see M11?
Answers.UserDisplayName: OverLordGoldDragon
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Answers.UserDisplayName: George Bland
Answers.Body: <p>What version of Stockfish are you using? I am using Stockfish 15.1, with Chessis Pro GUI on Android 13, Snapdragon 8 Gen 1, and it found the mate in few seconds with depth around 70.</p>
  <p>Edit: sorry, I missed the part where you say the version of the engine.</p>
  
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Answers.CreationDate: 2023-07-24T06:44:43.167Z
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Answers.UserDisplayName: Giulio Severini
Body: <p>I fed <a href="https://chess.stackexchange.com/a/42589/33019">@HaukeReddmann's &quot;hack&quot;</a> to <a href="https://chess.stackexchange.com/q/42581/33019">this scenario</a></p>
  <pre><code>[FEN &quot;8/p7/rp6/rp6/pP6/R7/8/K6k w - - 0 1&quot;]
  </code></pre>
  <p>to <a href="https://lichess.org/analysis/standard/8/p7/rp6/rp6/pP6/R7/8/K6k_w_-_-_0_1" rel="nofollow noreferrer">Lichess Stockfish 14</a>, white to move. Up to Depth 77 (after which I gave up waiting), it declares draw, and suggests <code>Ka2</code> as best move. Yet, the moment I play <code>Kb1</code>, it immediately realizes mate in 11 for white.</p>
  <p>Shouldn't 10 pieces be easy? Surely, eventually, it realizes M11 - but why not already with 38 (77/2) moves? And why doesn't Stockfish consider <code>Kb1</code> for itself (since it instantly realizes M11 when I play it)?</p>
  <p><strong>Clarifying</strong>, <a href="https://chess.stackexchange.com/a/37345/33019">this</a> explains my second question, but not quite the first and last. I get that ultimately it's heuristics, but is there something to specifically explain how it fails to find mate with just 10 pieces, <em>and</em> that me making the right move makes it see mate? Yes, longer wait (or better hardware, it runs on cloud) would help, so it's a question on efficiency (which moves it chooses to discard).</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-07-23T02:12:34.697Z
Comments.Text: Stockfish isn't designed to solve endgame puzzles, but play realistic games well.
Comments.UserDisplayName: qwr
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-07-23T06:17:08.207Z
Comments.Text: This https://chess.stackexchange.com/questions/37333/why-does-it-take-stockfish-depth-35-to-find-mate-in-7?rq=1 should answer your question (observed the same in the position, initially was as flabbergasted as you).
Comments.UserDisplayName: Hauke Reddmann
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-07-24T02:18:59.653Z
Comments.Text: @Allure Hmm sort of, though I'd prefer an answer to this more focused question.
Comments.UserDisplayName: OverLordGoldDragon
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-07-24T03:12:44.230Z
Comments.Text: What about this, does it answer your question? https://chess.stackexchange.com/questions/29417/why-are-world-class-engines-playing-like-this/39722#39722
Comments.UserDisplayName: Allure
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-07-24T03:27:53.253Z
Comments.Text: @Allure Well, an idea with Stack Exchange is direct answers to questions as-asked. If I have to dig much to find relevance, it's not a duplicate. An answer that merely cites an excerpt from another answer would count (likely along brief commentary).
Comments.UserDisplayName: OverLordGoldDragon
Tags: <endgame><stockfish><rook-endgame>
Title: Stockfish misses mate in 11 with 10 pieces
ThreadText: # Stockfish misses mate in 11 with 10 pieces
  
  (Asked by: username_0 on 2023-07-22)
  
  I fed @HaukeReddmann's "hack" to this scenario
  [FEN "8/p7/rp6/rp6/pP6/R7/8/K6k w - - 0 1"]
  
  to Lichess Stockfish 14, white to move. Up to Depth 77 (after which I gave up waiting), it declares draw, and suggests Ka2 as best move. Yet, the moment I play Kb1, it immediately realizes mate in 11 for white.
  Shouldn't 10 pieces be easy? Surely, eventually, it realizes M11 - but why not already with 38 (77/2) moves? And why doesn't Stockfish consider Kb1 for itself (since it instantly realizes M11 when I play it)?
  Clarifying, this explains my second question, but not quite the first and last. I get that ultimately it's heuristics, but is there something to specifically explain how it fails to find mate with just 10 pieces, and that me making the right move makes it see mate? Yes, longer wait (or better hardware, it runs on cloud) would help, so it's a question on efficiency (which moves it chooses to discard).
  
  **Tags:** endgame, stockfish, rook-endgame
  
  > **Comments:**
  > **username_1**: Stockfish isn't designed to solve endgame puzzles, but play realistic games well.  
  > **username_2**: This https://chess.stackexchange.com/questions/37333/why-does-it-take-stockfish-depth-35-to-find-mate-in-7?rq=1 should answer your question (observed the same in the position, initially was as flabbergasted as you).  
  > **username_0**: @username_3 Hmm sort of, though I'd prefer an answer to this more focused question.  
  > **username_3**: What about this, does it answer your question? https://chess.stackexchange.com/questions/29417/why-are-world-class-engines-playing-like-this/39722#39722  
  > **username_0**: @username_3 Well, an idea with Stack Exchange is direct answers to questions as-asked. If I have to dig much to find relevance, it's not a duplicate. An answer that merely cites an excerpt from another answer would count (likely along brief commentary).  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_4 on 2023-07-23. Score: 0
  
  My instance of Stockfish 16 saw M11 after about 7 seconds, so I think you just didn't wait long enough, although Stockfish 16 is stronger than 14 so that could also be why.
  
  > **Comments:**
  > **username_0**: Indeed that makes sense. Curious, at what search depth did it see M11?  
  
  ---
  
  ### Answer by username_5 on 2023-07-24. Score: 0
  
  What version of Stockfish are you using? I am using Stockfish 15.1, with Chessis Pro GUI on Android 13, Snapdragon 8 Gen 1, and it found the mate in few seconds with depth around 70.
  
  Edit: sorry, I missed the part where you say the version of the engine.
  
  
  ---
  
  