Answers.Body: <p>I also have PowerBook 2019, and Stockfish 10, and I can confirm what you found, but there is an explanation.</p>
  
  <p>The moves suggested in the PowerBook are from actual human games. They are intended, specifically, to give the computer a human opening book, rather than it just playing on its own. You will find these games in the database Powergames2019 that came with the product.</p>
  
  <p>This goes back to the old days, when computers were not as strong as they are today. It was then beneficial to have a human opening book. Today, one could make the argument that it is not so necessary.</p>
  
  <p>P.S. For the record, Masters have a natural proclivity not to block the c-pawn, either as white or black in closed openings since you need to play c5 so often to try and free your game. That is the reason the Chigorin is not so popular.</p>
  
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Answers.CreationDate: 2020-01-02T17:40:24.220Z
Answers.Text: I do agree about the c file in this setup, so that the real conclusion is : as this line of the opening (up to 4.Nf3) is not that fashionable, no one bothered studying the implications of the "unatural" 4...Nc6 sufficiently for seing it finally played. But I guess there are "unatural" moves found by engines that finally become standard human moves after analysis, right ?
Answers.UserDisplayName: Olórin
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Answers.Text: Exactly. Simply, no one has bothered to look at it yet. By the way, I have been a ChessBase user since version 1 back in 1990 or 1991.
Answers.UserDisplayName: PhishMaster
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Answers.UserDisplayName: PhishMaster
Answers.Body: <p>All engine/computer combinations have different strengths/weaknesses. </p>
  
  <p>That is a relatively  minor line and 5 .. Bd7 is better than Nf7 and was played by Bistric vs. Mestrovic ½-½ in 2001.   Looks more like a difference in the opening databases as much as anything else.  </p>
  
  <p>Or it could be a slight improvement to a weaker variation because the algorithm or evaluation technique changed.  Whether it is enough to help a GM win with is another issue.  I suspect other factors would determine the outcome of the game more than the engine or computer. </p>
  
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Answers.CreationDate: 2020-01-02T19:26:06.197Z
Answers.Text: You are missing the point. The question is not really about the engine: It is about why a reasonably strong move is not in the Powerbook2019, and that is because the Powerbook2019 is basically a compilation of openings from human games.
Answers.UserDisplayName: PhishMaster
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Answers.Text: I think I answered that.  Different databases, different algorithms, different management deciding what will sell more if they add it. It is what it is.  And IMHO it is still a minor variation in a weaker line or maybe a weaker line in a minor variation:)
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Answers.UserDisplayName: yobamamama
Body: <p>I am looking at 1.c4 Nf6 2.g3 d5 3.Bg2 dxc4 4.Nf3 and Chessbase's Powerbook 2019 only proposes 4...c6, 4...g6, 4...a6, 4...Nbd7, 4...Qd6 or 4...Be6 whereas Fritz 17 64bits latest update using Stockfish 10 64bits finds this line :</p>
  
  <p><a href="https://i.sstatic.net/wSYIF.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wSYIF.png" alt="enter image description here"></a></p>
  
  <pre><code>[fen ""]
  
  1.c4 Nf6 2.g3 d5 3.Bg2 dxc4 4.Nf3 Nc6 5.Qa4 Nd7 6.Qxc4 e5 7.O-O Be7 8.b3 Nb6 9.Qc2 O-O 10.Bb2 Nb4 11.Qc3 f6 12.a3 Nc6 13.d3 Be6 14.Nbd2 Qd7 15.Rac1 Rfd8 16.Qc2 a5 17.Rfd1 Bd5 18.Re1 Bf7 19.Ne4 h6 20.Nfd2 Be6 21.Red1 Bd5 22.Nc5 Bxc5 23.Qxc5 Bxg2 24.Kxg2 Kh8
  </code></pre>
  
  <p>Either the quality of the Powerbook 2019 is not that high, either Stockfish 10 64bits is cracking, which I doubt. Am I right or do I miss a parameter ?</p>
  
Tags: <software><stockfish><chessbase><english-opening><fritz>
Title: Early line in english opening not in the chessbase powerbook 2019 but seen by stockfish 10 64bits under latest fritz
ThreadText: # Early line in english opening not in the chessbase powerbook 2019 but seen by stockfish 10 64bits under latest fritz
  
  (Asked by: username_0 on 2020-01-02)
  
  I am looking at 1.c4 Nf6 2.g3 d5 3.Bg2 dxc4 4.Nf3 and Chessbase's Powerbook 2019 only proposes 4...c6, 4...g6, 4...a6, 4...Nbd7, 4...Qd6 or 4...Be6 whereas Fritz 17 64bits latest update using Stockfish 10 64bits finds this line :
  
  [fen ""]
  
  1.c4 Nf6 2.g3 d5 3.Bg2 dxc4 4.Nf3 Nc6 5.Qa4 Nd7 6.Qxc4 e5 7.O-O Be7 8.b3 Nb6 9.Qc2 O-O 10.Bb2 Nb4 11.Qc3 f6 12.a3 Nc6 13.d3 Be6 14.Nbd2 Qd7 15.Rac1 Rfd8 16.Qc2 a5 17.Rfd1 Bd5 18.Re1 Bf7 19.Ne4 h6 20.Nfd2 Be6 21.Red1 Bd5 22.Nc5 Bxc5 23.Qxc5 Bxg2 24.Kxg2 Kh8
  
  Either the quality of the Powerbook 2019 is not that high, either Stockfish 10 64bits is cracking, which I doubt. Am I right or do I miss a parameter ?
  
  **Tags:** software, stockfish, chessbase, english-opening, fritz
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2020-01-02. Score: 4 | Accepted answer
  
  I also have PowerBook 2019, and Stockfish 10, and I can confirm what you found, but there is an explanation.
  
  The moves suggested in the PowerBook are from actual human games. They are intended, specifically, to give the computer a human opening book, rather than it just playing on its own. You will find these games in the database Powergames2019 that came with the product.
  
  This goes back to the old days, when computers were not as strong as they are today. It was then beneficial to have a human opening book. Today, one could make the argument that it is not so necessary.
  
  P.S. For the record, Masters have a natural proclivity not to block the c-pawn, either as white or black in closed openings since you need to play c5 so often to try and free your game. That is the reason the Chigorin is not so popular.
  
  > **Comments:**
  > **username_0**: I do agree about the c file in this setup, so that the real conclusion is : as this line of the opening (up to 4.Nf3) is not that fashionable, no one bothered studying the implications of the "unatural" 4...Nc6 sufficiently for seing it finally played. But I guess there are "unatural" moves found by engines that finally become standard human moves after analysis, right ?  
  > **username_1**: Exactly. Simply, no one has bothered to look at it yet. By the way, I have been a ChessBase user since version 1 back in 1990 or 1991.  
  
  ---
  
  ### Answer by username_2 on 2020-01-02. Score: 0
  
  All engine/computer combinations have different strengths/weaknesses.
  
  That is a relatively minor line and 5 .. Bd7 is better than Nf7 and was played by Bistric vs. Mestrovic ½-½ in 2001. Looks more like a difference in the opening databases as much as anything else.
  
  Or it could be a slight improvement to a weaker variation because the algorithm or evaluation technique changed. Whether it is enough to help a GM win with is another issue. I suspect other factors would determine the outcome of the game more than the engine or computer.
  
  > **Comments:**
  > **username_1**: You are missing the point. The question is not really about the engine: It is about why a reasonably strong move is not in the Powerbook2019, and that is because the Powerbook2019 is basically a compilation of openings from human games.  
  > **username_2**: I think I answered that.  Different databases, different algorithms, different management deciding what will sell more if they add it. It is what it is.  And IMHO it is still a minor variation in a weaker line or maybe a weaker line in a minor variation:)  
  
  ---
  
  