Answers.Body: <p>They don't calculate the common openings, they know them by heart, at least the main lines, and the possible refutations, should the opponent deviate from the main line.</p>
  
  <p>For the less common openings, they might remember things not as deep as the often playable ones. Still, it's like 10-15 plys for something obnoxious and could be as much as 20-30 plys for the most common ones.</p>
  
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Answers.CreationDate: 2018-06-24T14:39:05.093Z
Answers.LastActivityDate: 2018-06-24T14:39:05.093Z
Answers.UserDisplayName: lenik
Answers.Body: <p>GMs have all the common opening memorized, sometimes to a very deep level.  In this regard, they are not calculating at all. Once they are out of their book, the depth of calculation is based upon the complexity of the board. When there aren't many pieces on the board, they don't always calculate so much as know that a certain situation is a win if they following certain principles.  In the middle game, 8 moves would be common, but the GM knows how to quickly remove from consideration variations that don't look promising. When they calculate deeper it is because they don't waste energy on bad variations.</p>
  
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Answers.CreationDate: 2018-06-24T14:34:23.870Z
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Answers.UserDisplayName: Tony Ennis
Answers.Body: <p>It depends, strong grandmasters might know tremendous amounts of lines by heart. Weaker GMs who no longer drill openings will forget majority of lines sooner or later but they will still be very good at recognizing strategic patterns and in making practical decisions. They will still know how to lure much weaker opposition into mess they will understand better while they will be able to limit seriously power of younger guys with better theoretical knowledge by sidestepping dangerous lines and limiting possible home preparation dangers. It's not that much about calculating in openings I guess.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-06-24T18:39:40.260Z
Answers.LastActivityDate: 2018-06-24T18:39:40.260Z
Answers.UserDisplayName: hoacin
Answers.Body: <p>When Richard Reti was asked how many moves ahead he calculated, his answer is said to have been "One, sometimes two". This is probably correct, if by "calculate" you mean examine all alternatives and be sure of the result.
  This is not what grandmasters do. What they actually do, nobody knows, not even them.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-06-24T17:55:25.530Z
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Answers.UserDisplayName: Philip Roe
Body: <p>How does a GM make his opening repertoire and how does he calculate his moves in advance.Can he calculate 20 moves in advance base on his opening?</p>
  
Tags: <opening>
Title: How does a GM calculate opening and how many moves in advance?
ThreadText: # How does a GM calculate opening and how many moves in advance?
  
  (Asked by: username_0 on 2018-06-24)
  
  How does a GM make his opening repertoire and how does he calculate his moves in advance.Can he calculate 20 moves in advance base on his opening?
  
  **Tags:** opening
  
  
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  ## 4 answers
  
  ### Answer by username_1 on 2018-06-24. Score: 2
  
  They don't calculate the common openings, they know them by heart, at least the main lines, and the possible refutations, should the opponent deviate from the main line.
  
  For the less common openings, they might remember things not as deep as the often playable ones. Still, it's like 10-15 plys for something obnoxious and could be as much as 20-30 plys for the most common ones.
  
  
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  ### Answer by username_2 on 2018-06-24. Score: 1
  
  GMs have all the common opening memorized, sometimes to a very deep level. In this regard, they are not calculating at all. Once they are out of their book, the depth of calculation is based upon the complexity of the board. When there aren't many pieces on the board, they don't always calculate so much as know that a certain situation is a win if they following certain principles. In the middle game, 8 moves would be common, but the GM knows how to quickly remove from consideration variations that don't look promising. When they calculate deeper it is because they don't waste energy on bad variations.
  
  
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  ### Answer by username_3 on 2018-06-24. Score: 1
  
  It depends, strong grandmasters might know tremendous amounts of lines by heart. Weaker GMs who no longer drill openings will forget majority of lines sooner or later but they will still be very good at recognizing strategic patterns and in making practical decisions. They will still know how to lure much weaker opposition into mess they will understand better while they will be able to limit seriously power of younger guys with better theoretical knowledge by sidestepping dangerous lines and limiting possible home preparation dangers. It's not that much about calculating in openings I guess.
  
  
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  ### Answer by username_4 on 2018-06-24. Score: 0
  
  When Richard Reti was asked how many moves ahead he calculated, his answer is said to have been "One, sometimes two". This is probably correct, if by "calculate" you mean examine all alternatives and be sure of the result.
  This is not what grandmasters do. What they actually do, nobody knows, not even them.
  
  
  ---
  
  