Answers.Body: <p>Its evaluation drops form +2.3 to +0.0, so it considers it a blunder. Of course this does not match what a human understands as &quot;blunder&quot;, but computers are incapable of identifying that.</p>
  <p>Your move is a perfectly reasonable one and if that's the biggest type of &quot;blunder&quot; you make in your games, you're on your way to a Grandmaster title.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-20T17:35:03.280Z
Answers.Text: But why does the evaluation drop to 0.0? White has clearly superior development, if nothing else. Something strange is going on here.
Answers.UserDisplayName: D M
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-21T01:50:00.207Z
Answers.Text: It is possible Nc6 leads to some (shallow analysis) line where Black comes under sustained pressure instead of an immediate Nf3 which can be partly nullified by Qd8 and a closed center where the two tempo disadvantage can be closed quickly. Lichess often marks blunders when it sees "shorter" variants - e.g a mate in 6 "blunder" when a more obscure mate in 5 is possible.
Answers.UserDisplayName: Fox
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-23T12:56:48.043Z
Answers.Text: Wanting to accept this answer but based on [this comment](https://chess.stackexchange.com/questions/35377/why-did-lichess-annotate-this-as-a-blunder#comment58128_35377), this answer wouldn't be the most useful to future readers in its current form.
Answers.UserDisplayName: SecretAgentMan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-19T22:17:42.547Z
Answers.LastActivityDate: 2021-06-19T22:17:42.547Z
Answers.UserDisplayName: David
Answers.Body: <p>The &quot;blunder&quot; annotation is derived from server-side analysis using a low engine depth, which is usually inaccurate.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-20T18:57:00.843Z
Answers.LastActivityDate: 2021-06-20T18:57:00.843Z
Answers.UserDisplayName: Aaaaaa
Body: <p>Lichess analysis annotated <strong>4. Nf3??</strong> as a blunder preferring (4. Nc3) (<a href="https://lichess.org/4BvYQXtK#6" rel="nofollow noreferrer">see on Lichess</a>). I am trying to understand the ideas that make this a blunder. At depth 23 with Stockfish 13+ NNEU, both were evaluated at +2.1.</p>
  <p>If you push the depth to 28, it begins to show a 0.1 preference for Nc3 over Nf3, but I still don't see how this evaluation disparity resulted in the blunder annotation.</p>
  <p>My thoughts:</p>
  <ul>
  <li><strong>4. Nf3</strong> continues development for White. Castling short becomes an option. Black has no immediate threat with the lone queen and must respond by moving the queen. This gives White the option to develop yet another piece. Black may fall behind in development.</li>
  <li>
  <ol start="4">
  <li>Nc3 also develops a piece but adds a protector to the e4 pawn which may come under attack after ...d5 .</li>
  </ol>
  </li>
  </ul>
  <p>I see no ideas that lead to a strong preference for one over the other. Am I missing some ideas in this position?</p>
  <p><sub> I realize that +/- 0.1 in an evaluation doesn't really mean a whole lot, but I am genuinely curious to learn if I'm missing an idea in the position.</sub></p>
  <p><sub> At depth 48, 4.Nf3 and 4.Nc3 are both top moves with equal evaluations </sub></p>
  <p>Edit: A <a href="https://chess.stackexchange.com/questions/35377/why-did-lichess-annotate-this-as-a-blunder#comment58101_35377">commenter</a> remarked &quot;<em>I don't believe it did</em>.&quot; I present a screenshot below proving this did occur.</p>
  <p><a href="https://i.sstatic.net/wRjLl.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wRjLl.jpg" alt="Lichess annotates 4. Nf3?? as a blunder." /></a></p>
  <pre><code>[Title &quot;White–Black (10 min) | ECO: B12 Caro-Kann Defense&quot;]
  [FEN &quot;&quot;]
  [startply &quot;6&quot;]
  
  1. e4 c6 2. d4 e6 3. Bd3 Qh4 4. Nf3 Qg4 5. O-O d5 6. Re1 Nf6 7. Nbd2 e5 8. exd5 Nxd5 9. Nxe5 (9. h3 Qe6 10. Rxe5) 9... Qg5 10. Nef3+ Qe7 11. Rxe7+ Bxe7 12. Qe1 O-O 13. Nc4 b5 14. Nce5 Nb4 15. Be4 Bb7 16. Qe3 Nd5 17. Bxh7+ Kh8 18. Qd2 Kxh7 19. Ng5+ Kg8 20. Qd3 Nd7 (20... Bxg5 21. Bxg5) 21. Nxd7 (21. Qh7#) 21... g6 22. Qh3 Nf6 (22... Bxg5) 23. Nxf8 (23. Qh6 Rfd8 24. Nxf6+ Bxf6 25. Qh7+ Kf8 26. Qxf7#) (23. Nxf6+ Kg7 24. Ngh7 g5 25. Bxg5 Kg6 26. g4 Kg7 27. Qh6+ Kh8 28. Nxf8#) 23... Bxf8 24. b3 Re8 25. Bb2 Nh5 26. d5 cxd5 27. c4 bxc4 28. Qc3 Ng7 29. Re1 Rc8 30. bxc4 (30. Qh3 Nh5 31. Qd7 Be7 32. Qxe7 Rf8 33. Qxf8+ Kxf8 34. Nh7+ Kg8 35. Re8+ Kxh7 36. Rh8#) 30... Rxc4 31. Qd3 Rb4 32. Rb1 (32. Qh3) 32... d4 33. Ne4 33... Ra4 33. Ne4 (33. Qh3) 33... Ra4 34. Ra1 (34. Nf6+) 34... Ba6 35. Nf6+ Kh8 36. Qh3+ Nh5 37. Nxh5 gxh5 38. Qxh5+
  </code></pre>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-19T16:58:13.383Z
Comments.Text: I hope I've met the standard for expectations of askers...if not, please comment and I will improve question to meet the standard.
Comments.UserDisplayName: SecretAgentMan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-19T17:34:00.740Z
Comments.Text: @adrasthea I have edited the question to provide a screenshot proving Lichess did indeed annotate this as a blunder.
Comments.UserDisplayName: SecretAgentMan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-19T18:38:12.280Z
Comments.Text: My Stockfish 11 likes `4) Nf3` the best after a 90 seconds of grinding.  lichess might consider Qh4 to be a blunder if its "what is a blunder" threshold is low.
Comments.UserDisplayName: Tony Ennis
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-19T20:47:57.780Z
Comments.Text: @RewanDemontay my mistake. I've included a link now.
Comments.UserDisplayName: SecretAgentMan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-20T09:49:04.737Z
Comments.Text: Please check at which depth the annotation has been calculated and evaluated. It might be that these ??s come from a very shallow analysis, and when you increase the depth, the evaluation changes of course, but the ?? signs remain.
Comments.UserDisplayName: sleepy
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-20T12:17:08.577Z
Comments.Text: My Lichess Stockfish is giving 4. Nf3 as the best move at depth 41, with 4. Nc3 second and 4. Qe2 third. In blitz I'd play 4. Nf3 without thinking twice, since it gains a tempo and so is "free".
Comments.UserDisplayName: Allure
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-20T17:34:31.490Z
Comments.Text: @sleepy When I run these same moves through Lichess's automatic computer analysis it gives me the same result as OP; it calls the move a blunder. I don't know what the depth of that automatic analysis is, though.
Comments.UserDisplayName: D M
Tags: <opening><engines><analysis><caro-kann><blunder>
Title: Why did Lichess annotate this as a blunder?
ThreadText: # Why did Lichess annotate this as a blunder?
  
  (Asked by: username_0 on 2021-06-19)
  
  Lichess analysis annotated 4. Nf3?? as a blunder preferring (4. Nc3) (see on Lichess). I am trying to understand the ideas that make this a blunder. At depth 23 with Stockfish 13+ NNEU, both were evaluated at +2.1.
  If you push the depth to 28, it begins to show a 0.1 preference for Nc3 over Nf3, but I still don't see how this evaluation disparity resulted in the blunder annotation.
  My thoughts:
  
  4. Nf3 continues development for White. Castling short becomes an option. Black has no immediate threat with the lone queen and must respond by moving the queen. This gives White the option to develop yet another piece. Black may fall behind in development.
  
  
  Nc3 also develops a piece but adds a protector to the e4 pawn which may come under attack after ...d5 .
  
  
  
  I see no ideas that lead to a strong preference for one over the other. Am I missing some ideas in this position?
   I realize that +/- 0.1 in an evaluation doesn't really mean a whole lot, but I am genuinely curious to learn if I'm missing an idea in the position.
   At depth 48, 4.Nf3 and 4.Nc3 are both top moves with equal evaluations 
  Edit: A commenter remarked "I don't believe it did." I present a screenshot below proving this did occur.
  
  [Title "White–Black (10 min) | ECO: B12 Caro-Kann Defense"]
  [FEN ""]
  [startply "6"]
  
  1. e4 c6 2. d4 e6 3. Bd3 Qh4 4. Nf3 Qg4 5. O-O d5 6. Re1 Nf6 7. Nbd2 e5 8. exd5 Nxd5 9. Nxe5 (9. h3 Qe6 10. Rxe5) 9... Qg5 10. Nef3+ Qe7 11. Rxe7+ Bxe7 12. Qe1 O-O 13. Nc4 b5 14. Nce5 Nb4 15. Be4 Bb7 16. Qe3 Nd5 17. Bxh7+ Kh8 18. Qd2 Kxh7 19. Ng5+ Kg8 20. Qd3 Nd7 (20... Bxg5 21. Bxg5) 21. Nxd7 (21. Qh7#) 21... g6 22. Qh3 Nf6 (22... Bxg5) 23. Nxf8 (23. Qh6 Rfd8 24. Nxf6+ Bxf6 25. Qh7+ Kf8 26. Qxf7#) (23. Nxf6+ Kg7 24. Ngh7 g5 25. Bxg5 Kg6 26. g4 Kg7 27. Qh6+ Kh8 28. Nxf8#) 23... Bxf8 24. b3 Re8 25. Bb2 Nh5 26. d5 cxd5 27. c4 bxc4 28. Qc3 Ng7 29. Re1 Rc8 30. bxc4 (30. Qh3 Nh5 31. Qd7 Be7 32. Qxe7 Rf8 33. Qxf8+ Kxf8 34. Nh7+ Kg8 35. Re8+ Kxh7 36. Rh8#) 30... Rxc4 31. Qd3 Rb4 32. Rb1 (32. Qh3) 32... d4 33. Ne4 33... Ra4 33. Ne4 (33. Qh3) 33... Ra4 34. Ra1 (34. Nf6+) 34... Ba6 35. Nf6+ Kh8 36. Qh3+ Nh5 37. Nxh5 gxh5 38. Qxh5+
  
  **Tags:** opening, engines, analysis, caro-kann, blunder
  
  > **Comments:**
  > **username_0**: I hope I've met the standard for expectations of askers...if not, please comment and I will improve question to meet the standard.  
  > **username_0**: @adrasthea I have edited the question to provide a screenshot proving Lichess did indeed annotate this as a blunder.  
  > **username_1**: My Stockfish 11 likes `4) Nf3` the best after a 90 seconds of grinding.  lichess might consider Qh4 to be a blunder if its "what is a blunder" threshold is low.  
  > **username_0**: @RewanDemontay my mistake. I've included a link now.  
  > **username_2**: Please check at which depth the annotation has been calculated and evaluated. It might be that these ??s come from a very shallow analysis, and when you increase the depth, the evaluation changes of course, but the ?? signs remain.  
  > **username_3**: My Lichess Stockfish is giving 4. Nf3 as the best move at depth 41, with 4. Nc3 second and 4. Qe2 third. In blitz I'd play 4. Nf3 without thinking twice, since it gains a tempo and so is "free".  
  > **username_4**: @username_2 When I run these same moves through Lichess's automatic computer analysis it gives me the same result as OP; it calls the move a blunder. I don't know what the depth of that automatic analysis is, though.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_7 on 2021-06-20. Score: 8 | Accepted answer
  
  The "blunder" annotation is derived from server-side analysis using a low engine depth, which is usually inaccurate.
  
  
  ---
  
  ### Answer by username_5 on 2021-06-19. Score: 13
  
  Its evaluation drops form +2.3 to +0.0, so it considers it a blunder. Of course this does not match what a human understands as "blunder", but computers are incapable of identifying that.
  
  Your move is a perfectly reasonable one and if that's the biggest type of "blunder" you make in your games, you're on your way to a Grandmaster title.
  
  > **Comments:**
  > **username_4**: But why does the evaluation drop to 0.0? White has clearly superior development, if nothing else. Something strange is going on here.  
  > **username_6**: It is possible Nc6 leads to some (shallow analysis) line where Black comes under sustained pressure instead of an immediate Nf3 which can be partly nullified by Qd8 and a closed center where the two tempo disadvantage can be closed quickly. Lichess often marks blunders when it sees "shorter" variants - e.g a mate in 6 "blunder" when a more obscure mate in 5 is possible.  
  > **username_0**: Wanting to accept this answer but based on [this comment](https://chess.stackexchange.com/questions/35377/why-did-lichess-annotate-this-as-a-blunder#comment58128_35377), this answer wouldn't be the most useful to future readers in its current form.  
  
  ---
  
  