Answers.Body: <h2>In short, the key idea is to <strong>prevent white from playing <code>h2-h3</code></strong>!</h2>
  
  <p><code>Bc4</code> forces the exchange of light square bishops, and thus, sets up <code>Rh3</code> which blocks the <code>h2</code> pawn and keeps both the <code>h2</code> and <code>g4</code> pawns weak.
  Concretely, the only piece currently covering <code>h3</code> is the light squared bishop on <code>f1</code>, so by trading the bishop with <code>Bc4</code>, which white cannot prevent as <code>Bg2</code> leaves <code>h2</code> hanging, white has no immediate means (e.g. a rook on <code>g3</code> would prepare <code>h3</code> but it's too slow) of preventing black's imminent <code>Rh3</code>.</p>
  
  <p><a href="https://i.sstatic.net/nFeMMm.png" rel="noreferrer"><img src="https://i.sstatic.net/nFeMMm.png" alt="enter image description here"></a></p>
  
  <p><strong>Black's bigger idea is to create two connected central passed pawns!</strong> </p>
  
  <p>More precisely, the plan is: </p>
  
  <ul>
  <li>to pressure <code>g4</code>, and binding white's rooks to the defense of <code>g4</code> and <code>h2</code>,</li>
  <li>bring the king to <code>e6</code> to prepare the <code>d5</code> advance to trade the <code>e4</code> pawn, then go back to <code>e6</code> and similarly prepare trading white's <code>g4</code> pawn with <code>f5</code>,</li>
  <li>after which black is left with a passed <code>f</code> and <code>e</code> pawn, that is, two connected passed pawns!</li>
  </ul>
  
  <p><a href="https://i.sstatic.net/wXjkAm.png" rel="noreferrer"><img src="https://i.sstatic.net/wXjkAm.png" alt="enter image description here"></a></p>
  
  <p>Suppose <code>Bc4</code> is not played, then white gets to play <code>h3</code>, and thus maintaining their bind on light squares and killing black's prospect of
  creating two connected passers. 
  In the game itself, Ivanchuck decided to trade the <code>g</code>-pawn quickly (by advancing it to <code>g5</code>) in order to get rid of one of his weak pawns, after which Anand still managed to execute his plan as all he had to ensure was trading the <code>e4</code> pawn by playing <code>d5</code>. Here's the position that transpired in the actual game, where Anand's plan has been executed to perfection:</p>
  
  <p><a href="https://i.sstatic.net/BNrPjm.png" rel="noreferrer"><img src="https://i.sstatic.net/BNrPjm.png" alt="enter image description here"></a></p>
  
  <p>Quite an exemplary game showing Anand's deep positional understanding: note the move <code>Bc4</code> a priori undermines a couple of chess principles:
  it willingly trades black's only good bishop, after which black is left with a hemmed-in dark squared bishop vs white's active one. Moreover, black allows
  their queenside pawns to become shattered into 2 (isolated) islands, and in doing so having less chance of dominating<sup>1</sup> <code>2-vs-3</code> on the queenside. </p>
  
  <p>In spite of all these at-first-glance-unfavourable aspects of the move, Anand beautifully realised controlling the <code>h3</code> square outweighs them all, since preventing white's <code>h2-h3</code> pawn advance to support <code>g4</code> is the only way black can maintain the prospect of active play in the pawn skeleton that had transpired, as we discussed above.</p>
  
  <p>Here's the game itself:</p>
  
  <pre><code> [title "Continuation after 20...Bc4"]
   [fen ""]
   [startply "40"]
  
   1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2 a6 8. O-O-O h6 9. Be3 Nxd4 10. Bxd4 b5 11. f3 Qa5 12. a3 e5 13. Be3 Be6 14. Kb1 Be7 15. g4 Rb8 16. Nd5 Qxd2 17. Nxf6+ gxf6 18. Rxd2 h5 19. Rg1 hxg4 20. fxg4 Bc4 21. b3 Bxf1 22. Rxf1 Rh3 23. Re2 Kd7 24. g5 Ke6 25. gxf6 Bxf6 26. Bd2 Be7 27. Be1 f6 28. Bg3 d5 29. exd5+ Kxd5 30. Rf5 Kc6 31. Ref2 Rh6 32. Kb2 Kd7 33. Re2 Bd6 34. Rf3 Rc8 35. Be1 Ke6 36. Rd3 Rh7 37. Rg3 Bc5 38. Ka2 Rd7 39. Rc3 Rcc7 40. h4 Rd1 41. Bf2 Bd6 42. Rg3 e4 43. Rxe4+ Be5 44. Rxe5+ fxe5 45. Kb2 Rd2 0-1
  </code></pre>
  
  <hr>
  
  <p><sup><sup>1</sup>: <em>Domination</em> in this context means: the side with the minority (less pawns) achieving a setup (e.g. a blockade) where neither of the majority pawns of the opponent can (easily) advance. Typical to the Sicilian pawn structure on the queenside, one such setup could be white's pawns being on <code>a2-b3-c2</code> and black's pawns pinning down on dark squares with <code>a5-b4.</code> For an example see the setup by Caruana (as black) in his <a href="https://www.chessgames.com/perl/chessgame?gid=1818557" rel="noreferrer">candidates game vs Karjakin</a> (e.g. around move <code>22</code>), where indeed one of his positional mistakes in that game was to give up the domination with <code>26...a4.</code> </sup></p>
  
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Answers.Text: @PhishMaster [lichess analysis board](https://lichess.org/analysis): change board theme to blue-white, square highlights or arrows are drawn with the mouse right-click. The default color is green, additionally, you can hold shift for red or alt for blue. The images are then simply screenshots of the board.
Answers.UserDisplayName: Ellie
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Answers.Text: Thank you very much, this has been most insightful!
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Answers.Body: <p>Phonon's answer is great, and I might not otherwise try to add anything, but I thought that adding Anand's own words might be worthy. In particular, of note, is that his "bad" Be7 holds his position together while his rooks go to work. This is not uncommon in Sicilian lines with d6 and e5 (and f6), and worth remembering if you play similar lines.</p>
  
  <p>So, here are Anand's own words about 20...Bc4!! (his own exclams): "In time to stop white getting some sort of fortress in the kingside. Black's `bad' bishop will protect his pawns while he exchanges towards connected h and g passers."</p>
  
  <p>I wonder if he meant e and f passers, but he also, clearly, envisioned that e and f would be come strong, and he only gave one up before they started to roll because it forced the win of the exchange.</p>
  
  <p>Lastly, Anand notes that had white exchanged on c4, with 21. Bc4 bc 22. Rd5 trying to go after a5 or c4 (after Ra5-a4), he intended to stop all counterplay with Rb5 (the computer likes the immediate Rxh2 as over +2).</p>
  
  <pre><code> [title "Ivanchuk vs Anand 1992 variation"]
   [fen "1r2k2r/4bp2/p2pbp2/1p2p3/4P1P1/P3B3/1PPR3P/1K3BR1 b k - 0 20"]
  
   1...Bc4 2. Bxc4 bxc4 {idea c3-+} 3. Rd5 Rb5 {Anand, but equal per the computer} (3...Rh2 4. Ra5 Re2 5. Rg3 Kd7 6. Rxa6 Rh8 {with an overwhelming advantage due to the active rooks, and unsafe white king.})
  </code></pre>
  
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Body: <p>In the <a href="https://www.chessgames.com/perl/chessgame?gid=1060292" rel="noreferrer">Ivanchuk vs Anand game (1992)</a>, the game leads into an endgame after lots of exchanges, which by no means looks (to me at least) winning for black: they both have 2 rooks, 2 bishops, and black has a rather awkward pawn structure in the center with the doubled f-pawns and the light square holes. Nonetheless, Anand decided to trade his bishop by playing Bc4 (shown in diagram below), and managed to win the game afterwards quite convincingly and rather seamlessly!</p>
  
  <ul>
  <li>But what is Anand's plan with the move Bc4? And how is it that black could suddenly build such a strong edge in the endgame thereafter? </li>
  </ul>
  
  <p>Diagram:</p>
  
  <pre><code> [title "Ivanchuk vs Anand 1992"]
   [fen "1r2k2r/4bp2/p2pbp2/1p2p3/4P1P1/P3B3/1PPR3P/1K3BR1 b k - 0 20"]
  
   1...Bc4
  </code></pre>
  
Tags: <endgame><positional-play><anand>
Title: Understanding Anand's Bc4 move vs Ivanchuk 1992
ThreadText: # Understanding Anand's Bc4 move vs Ivanchuk 1992
  
  (Asked by: username_0 on 2020-01-12)
  
  In the Ivanchuk vs Anand game (1992), the game leads into an endgame after lots of exchanges, which by no means looks (to me at least) winning for black: they both have 2 rooks, 2 bishops, and black has a rather awkward pawn structure in the center with the doubled f-pawns and the light square holes. Nonetheless, Anand decided to trade his bishop by playing Bc4 (shown in diagram below), and managed to win the game afterwards quite convincingly and rather seamlessly!
  
  But what is Anand's plan with the move Bc4? And how is it that black could suddenly build such a strong edge in the endgame thereafter? 
  
  Diagram:
   [title "Ivanchuk vs Anand 1992"]
   [fen "1r2k2r/4bp2/p2pbp2/1p2p3/4P1P1/P3B3/1PPR3P/1K3BR1 b k - 0 20"]
  
   1...Bc4
  
  **Tags:** endgame, positional-play, anand
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2020-01-12. Score: 29
  
  In short, the key idea is to prevent white from playing h2-h3!
  Bc4 forces the exchange of light square bishops, and thus, sets up Rh3 which blocks the h2 pawn and keeps both the h2 and g4 pawns weak.
  Concretely, the only piece currently covering h3 is the light squared bishop on f1, so by trading the bishop with Bc4, which white cannot prevent as Bg2 leaves h2 hanging, white has no immediate means (e.g. a rook on g3 would prepare h3 but it's too slow) of preventing black's imminent Rh3.
  
  Black's bigger idea is to create two connected central passed pawns! 
  More precisely, the plan is: 
  
  to pressure g4, and binding white's rooks to the defense of g4 and h2,
  bring the king to e6 to prepare the d5 advance to trade the e4 pawn, then go back to e6 and similarly prepare trading white's g4 pawn with f5,
  after which black is left with a passed f and e pawn, that is, two connected passed pawns!
  
  
  Suppose Bc4 is not played, then white gets to play h3, and thus maintaining their bind on light squares and killing black's prospect of
  creating two connected passers. 
  In the game itself, Ivanchuck decided to trade the g-pawn quickly (by advancing it to g5) in order to get rid of one of his weak pawns, after which Anand still managed to execute his plan as all he had to ensure was trading the e4 pawn by playing d5. Here's the position that transpired in the actual game, where Anand's plan has been executed to perfection:
  
  Quite an exemplary game showing Anand's deep positional understanding: note the move Bc4 a priori undermines a couple of chess principles:
  it willingly trades black's only good bishop, after which black is left with a hemmed-in dark squared bishop vs white's active one. Moreover, black allows
  their queenside pawns to become shattered into 2 (isolated) islands, and in doing so having less chance of dominating1 2-vs-3 on the queenside. 
  In spite of all these at-first-glance-unfavourable aspects of the move, Anand beautifully realised controlling the h3 square outweighs them all, since preventing white's h2-h3 pawn advance to support g4 is the only way black can maintain the prospect of active play in the pawn skeleton that had transpired, as we discussed above.
  Here's the game itself:
   [title "Continuation after 20...Bc4"]
   [fen ""]
   [startply "40"]
  
   1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2 a6 8. O-O-O h6 9. Be3 Nxd4 10. Bxd4 b5 11. f3 Qa5 12. a3 e5 13. Be3 Be6 14. Kb1 Be7 15. g4 Rb8 16. Nd5 Qxd2 17. Nxf6+ gxf6 18. Rxd2 h5 19. Rg1 hxg4 20. fxg4 Bc4 21. b3 Bxf1 22. Rxf1 Rh3 23. Re2 Kd7 24. g5 Ke6 25. gxf6 Bxf6 26. Bd2 Be7 27. Be1 f6 28. Bg3 d5 29. exd5+ Kxd5 30. Rf5 Kc6 31. Ref2 Rh6 32. Kb2 Kd7 33. Re2 Bd6 34. Rf3 Rc8 35. Be1 Ke6 36. Rd3 Rh7 37. Rg3 Bc5 38. Ka2 Rd7 39. Rc3 Rcc7 40. h4 Rd1 41. Bf2 Bd6 42. Rg3 e4 43. Rxe4+ Be5 44. Rxe5+ fxe5 45. Kb2 Rd2 0-1
  
  
  1: Domination in this context means: the side with the minority (less pawns) achieving a setup (e.g. a blockade) where neither of the majority pawns of the opponent can (easily) advance. Typical to the Sicilian pawn structure on the queenside, one such setup could be white's pawns being on a2-b3-c2 and black's pawns pinning down on dark squares with a5-b4. For an example see the setup by Caruana (as black) in his candidates game vs Karjakin (e.g. around move 22), where indeed one of his positional mistakes in that game was to give up the domination with 26...a4.
  
  > **Comments:**
  > **username_2**: What do you use to make those nice images? Thanks.  
  > **username_1**: @username_2 [lichess analysis board](https://lichess.org/analysis): change board theme to blue-white, square highlights or arrows are drawn with the mouse right-click. The default color is green, additionally, you can hold shift for red or alt for blue. The images are then simply screenshots of the board.  
  > **username_0**: Thank you very much, this has been most insightful!  
  
  ---
  
  ### Answer by username_2 on 2020-01-12. Score: 10
  
  Phonon's answer is great, and I might not otherwise try to add anything, but I thought that adding Anand's own words might be worthy. In particular, of note, is that his "bad" Be7 holds his position together while his rooks go to work. This is not uncommon in Sicilian lines with d6 and e5 (and f6), and worth remembering if you play similar lines.
  So, here are Anand's own words about 20...Bc4!! (his own exclams): "In time to stop white getting some sort of fortress in the kingside. Black's `bad' bishop will protect his pawns while he exchanges towards connected h and g passers."
  I wonder if he meant e and f passers, but he also, clearly, envisioned that e and f would be come strong, and he only gave one up before they started to roll because it forced the win of the exchange.
  Lastly, Anand notes that had white exchanged on c4, with 21. Bc4 bc 22. Rd5 trying to go after a5 or c4 (after Ra5-a4), he intended to stop all counterplay with Rb5 (the computer likes the immediate Rxh2 as over +2).
   [title "Ivanchuk vs Anand 1992 variation"]
   [fen "1r2k2r/4bp2/p2pbp2/1p2p3/4P1P1/P3B3/1PPR3P/1K3BR1 b k - 0 20"]
  
   1...Bc4 2. Bxc4 bxc4 {idea c3-+} 3. Rd5 Rb5 {Anand, but equal per the computer} (3...Rh2 4. Ra5 Re2 5. Rg3 Kd7 6. Rxa6 Rh8 {with an overwhelming advantage due to the active rooks, and unsafe white king.})
  
  
  ---
  
  