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.CreationDate: 2023-07-23T22:03:46.257Z
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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.LastEditDate: 2023-07-24T06:45:43.957Z
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 [@username_2's "hack"](https://chess.stackexchange.com/a/42589/33019) to [this scenario](https://chess.stackexchange.com/q/42581/33019)
  
  ```
  [FEN "8/p7/rp6/rp6/pP6/R7/8/K6k w - - 0 1"]
  
  ```
  
  to [Lichess Stockfish 14](https://lichess.org/analysis/standard/8/p7/rp6/rp6/pP6/R7/8/K6k_w_-_-_0_1), 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](https://chess.stackexchange.com/a/37345/33019) 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.
  
  
  ---
  
  