Answers.Body: <p>History of this line is interesting. People used to think it's good for white, maybe majority still do as well as openings books do. But in correspondence database I use there are four games with Nxe6 fxe6 and black scored two wins and two draws out of four games. The wins are from 2012 and 2013. I know a lot of white players avoiding the sacrifice these days as it is easy to lose even against much weaker opposition while it doesn't even have the objective quality. Black play is easier and more obvious. I don't like White's position, I like Black here. It is too closed without direct threats for such a material investment. I know mainly the defensive plans for black here as it is in my repertoire, ok white try to play on e-file, disrupt you with Ne5 and f7 fork threat, may want to play c5 with B/Qa5+ sometimes and even b2-b4-b5 as black is undeveloped for quite some time. It is positional sacrifice and very interesting one. </p>
  
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Answers.CreationDate: 2017-06-15T16:22:11.950Z
Answers.Text: Such sacrifices are usually "bad in theory but good in practice". Black is a human player, who cannot calculate all lines and threats, and may at some point make a small mistake. If white is better prepared, he has good winning chances. (In correspondence games it is less likely with the enormous time available for black to analyze the position.)
Answers.UserDisplayName: TMM
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Answers.Text: @TMM That's too one sided comment. Black will be usually prepared very well here, playing sideline of sideline with well known piece sacrifice with king on e7 after few moves. White, on the other hand, is just following the main line, maybe saw a little analysis five year ago. Black made the choice to go here much more than white. Black is probably quite confident in defense. There are practical and unpractical positions, but this one is not unpractical for black unless he is really bad in defense. One small mistake by white and it's over, piece down.
Answers.UserDisplayName: hoacin
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Answers.Text: Of course there are two sides to it, and if black is better prepared than white, then black will win. But you're right, maybe this position is as hard to play accurately for white (to create enough play) as it is for black (to defend).
Answers.UserDisplayName: TMM
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Answers.CreationDate: 2017-06-15T06:01:52.913Z
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Answers.UserDisplayName: hoacin
Answers.Body: <p>Honestly the Sacrifice of the Knight compensates with one pawn and a check of Bg6+ which forces the King to an unhealthy square of e7 . There is definitely an initiative which White has in the rest of the game but I will suggest that this move order is good for players like Mikhail Tal / Robert Spielmann / Rashid Nezhmetinov who has a daring style of play and sacrifice is their main weapon in major chess games . It is indeed difficult to answer and no fixed algorithm as how White will bring out the game and win it . Infact it could be Black who has better chances . </p>
  
  <p>True Black is cramped with King in Centre but Black has all its pieces surrounded and White has nothing except a Bishop on g6 which takes off some squares but with good play Black should be able to neutralize White's attack .After Qc7 or Qa5 Black's king will be safe on d8 with no immediate attack from White . </p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-06-28T18:23:23.323Z
Answers.Text: History might have been different if only Kasparov could have had the benefit of your sage advice
Answers.UserDisplayName: Philip Roe
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Answers.CreationDate: 2017-06-29T08:34:42.750Z
Answers.Text: @PhilipRoe...Do not get bothered as to what Kasparov would do ...Let me remind you that this forum is for people like u & me ...Kasparov is just too great to be handed by Chess Stack Exchange Community .
Answers.UserDisplayName: Seth Projnabrata
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-06-30T12:51:37.977Z
Answers.Text: So in that case where is the value in your opinion? Or mine? We already have Kasparovs
Answers.UserDisplayName: Philip Roe
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-06-30T16:08:57.240Z
Answers.Text: My opinion has value yours also has , but History won't be bothered by it unless we are some prime players and yes as Mikhail Tal said that " Minutes of a Game and Days of Analysis are two different things " . So it is easy to suggest comments of GM level games even for Amatuers like me but to play accordingly is a different thing .
Answers.UserDisplayName: Seth Projnabrata
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-06-15T09:45:28.803Z
Answers.LastActivityDate: 2017-06-15T09:45:28.803Z
Answers.UserDisplayName: Seth Projnabrata
Body: <p>Below is the 1997 game of Deep Blue VS Garry Kasparov:</p>
  
  <pre><code>r1bqkb1r/pp1n1pp1/2p1pn1p/6N1/3P4/3B1N2/PPP2PPP/R1BQK2R w - - 0 1
  </code></pre>
  
  <p>The last move <code>7...h6?</code> was played by Kasparov (black), after which Deep Blue played the knight sacrifice 8.Nxe6.</p>
  
  <p>Wikipedia says:</p>
  
  <blockquote>
    <p>The computer is aided by having this knight sacrifice programmed into its opening book. This move had been played in a number of previous high-level games, with white achieving a huge plus score. As an indication of how far computer chess has progressed in the 20 years after this match, modern programs deprived of their opening books are able to correctly evaluate Nxe6 as strongest; but at the time this was played it was considered probable based on other programs' performance that it was only the opening book that was responsible for this choice. The compensation white gets for the material is not obvious enough for the computer to see by itself.</p>
  </blockquote>
  
  <p>How would white compensate for their sacrificed knight?</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-06-15T03:07:30.123Z
Comments.Text: If you know this was played in a Deep Blue-Kasparov game, why not look up that game and see how white obtained compensation or how black had difficulties consolidating his extra piece?
Comments.UserDisplayName: TMM
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-06-15T03:10:18.477Z
Comments.Text: As for things that come to mind to me without checking that game: white obtains a pawn, and white can follow up with Bg6+, forcing the king to the awkward square e7 where it is (a) not safe, (b) hinders development of e.g. the f8 bishop, and (c) can no longer be brought to safety through castling. Slightly less concrete compensation: the kingside light squares for black are weak (f7, g6, e6) which white might at some point hope to exploit with e.g. landing a knight fork on f7 or g6, or just attacking the e6-pawn. It is crucial for white to develop quickly and pressurize black.
Comments.UserDisplayName: TMM
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-06-15T15:05:48.253Z
Comments.Text: @TMM I couldn't because as you know Kasparov resigned after 19 moves and in these moves there was no compensation.
Comments.UserDisplayName: Wais Kamal
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-06-15T16:18:11.253Z
Comments.Text: There was no compensation? So Kasparov resigned in a winning position? Think again.
Comments.UserDisplayName: TMM
Tags: <analysis><sacrifice>
Title: Knight sacrifice performed by Deep Blue against Garry Kasparov
ThreadText: # Knight sacrifice performed by Deep Blue against Garry Kasparov
  
  (Asked by: username_0 on 2017-06-15)
  
  Below is the 1997 game of Deep Blue VS Garry Kasparov:
  
  ```
  r1bqkb1r/pp1n1pp1/2p1pn1p/6N1/3P4/3B1N2/PPP2PPP/R1BQK2R w - - 0 1
  
  ```
  
  The last move `7...h6?` was played by Kasparov (black), after which Deep Blue played the knight sacrifice 8.Nxe6.
  
  Wikipedia says:
  
  > The computer is aided by having this knight sacrifice programmed into its opening book. This move had been played in a number of previous high-level games, with white achieving a huge plus score. As an indication of how far computer chess has progressed in the 20 years after this match, modern programs deprived of their opening books are able to correctly evaluate Nxe6 as strongest; but at the time this was played it was considered probable based on other programs' performance that it was only the opening book that was responsible for this choice. The compensation white gets for the material is not obvious enough for the computer to see by itself.
  
  How would white compensate for their sacrificed knight?
  
  **Tags:** analysis, sacrifice
  
  > **Comments:**
  > **username_1**: If you know this was played in a Deep Blue-Kasparov game, why not look up that game and see how white obtained compensation or how black had difficulties consolidating his extra piece?  
  > **username_1**: As for things that come to mind to me without checking that game: white obtains a pawn, and white can follow up with Bg6+, forcing the king to the awkward square e7 where it is (a) not safe, (b) hinders development of e.g. the f8 bishop, and (c) can no longer be brought to safety through castling. Slightly less concrete compensation: the kingside light squares for black are weak (f7, g6, e6) which white might at some point hope to exploit with e.g. landing a knight fork on f7 or g6, or just attacking the e6-pawn. It is crucial for white to develop quickly and pressurize black.  
  > **username_0**: @username_1 I couldn't because as you know Kasparov resigned after 19 moves and in these moves there was no compensation.  
  > **username_1**: There was no compensation? So Kasparov resigned in a winning position? Think again.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2017-06-15. Score: 5 | Accepted answer
  
  History of this line is interesting. People used to think it's good for white, maybe majority still do as well as openings books do. But in correspondence database I use there are four games with Nxe6 fxe6 and black scored two wins and two draws out of four games. The wins are from 2012 and 2013. I know a lot of white players avoiding the sacrifice these days as it is easy to lose even against much weaker opposition while it doesn't even have the objective quality. Black play is easier and more obvious. I don't like White's position, I like Black here. It is too closed without direct threats for such a material investment. I know mainly the defensive plans for black here as it is in my repertoire, ok white try to play on e-file, disrupt you with Ne5 and f7 fork threat, may want to play c5 with B/Qa5+ sometimes and even b2-b4-b5 as black is undeveloped for quite some time. It is positional sacrifice and very interesting one.
  
  > **Comments:**
  > **username_1**: Such sacrifices are usually "bad in theory but good in practice". Black is a human player, who cannot calculate all lines and threats, and may at some point make a small mistake. If white is better prepared, he has good winning chances. (In correspondence games it is less likely with the enormous time available for black to analyze the position.)  
  > **username_2**: @username_1 That's too one sided comment. Black will be usually prepared very well here, playing sideline of sideline with well known piece sacrifice with king on e7 after few moves. White, on the other hand, is just following the main line, maybe saw a little analysis five year ago. Black made the choice to go here much more than white. Black is probably quite confident in defense. There are practical and unpractical positions, but this one is not unpractical for black unless he is really bad in defense. One small mistake by white and it's over, piece down.  
  > **username_1**: Of course there are two sides to it, and if black is better prepared than white, then black will win. But you're right, maybe this position is as hard to play accurately for white (to create enough play) as it is for black (to defend).  
  
  ---
  
  ### Answer by username_3 on 2017-06-15. Score: 1
  
  Honestly the Sacrifice of the Knight compensates with one pawn and a check of Bg6+ which forces the King to an unhealthy square of e7 . There is definitely an initiative which White has in the rest of the game but I will suggest that this move order is good for players like Mikhail Tal / Robert Spielmann / Rashid Nezhmetinov who has a daring style of play and sacrifice is their main weapon in major chess games . It is indeed difficult to answer and no fixed algorithm as how White will bring out the game and win it . Infact it could be Black who has better chances .
  
  True Black is cramped with King in Centre but Black has all its pieces surrounded and White has nothing except a Bishop on g6 which takes off some squares but with good play Black should be able to neutralize White's attack .After Qc7 or Qa5 Black's king will be safe on d8 with no immediate attack from White .
  
  > **Comments:**
  > **username_4**: History might have been different if only Kasparov could have had the benefit of your sage advice  
  > **username_3**: @username_4...Do not get bothered as to what Kasparov would do ...Let me remind you that this forum is for people like u & me ...Kasparov is just too great to be handed by Chess Stack Exchange Community .  
  > **username_4**: So in that case where is the value in your opinion? Or mine? We already have Kasparovs  
  > **username_3**: My opinion has value yours also has , but History won't be bothered by it unless we are some prime players and yes as Mikhail Tal said that " Minutes of a Game and Days of Analysis are two different things " . So it is easy to suggest comments of GM level games even for Amatuers like me but to play accordingly is a different thing .  
  
  ---
  
  