Answers.Body: <h2>tl;dr: Wrong move order by black in the opening: the c4 advance must be prefaced with Nd7 in the played Zaitsev variation.</h2>
  
  <p>That said, and although your hunch about the early <code>c4</code> is correct, I'm afraid there's no simple answer that immediately explains why the immediate <code>c4</code> is bad and why <code>Nd7</code> is so crucial, since the <a href="https://en.wikipedia.org/wiki/Ruy_Lopez" rel="nofollow noreferrer">Ruy Lopez</a> and the Zaitsev are highly theoretical openings and thus, all about nuances and concrete assessments. </p>
  
  <p><em>In any case, here's an attempt to answer it in a simplified manner.</em></p>
  
  <p><strong>Bit of context first:</strong> the game started out as a classical Ruy Lopez which then transitioned into <a href="https://en.wikipedia.org/wiki/Ruy_Lopez#Zaitsev_Variation:_9.h3_Bb7" rel="nofollow noreferrer">the Zaitsev variation</a>. Then in particular after <code>11...Bf8</code>, Firouzja opted for the older system with <code>12.a4</code> which is 
  a variation rich in theory dating specially back to the Kasparov-Karpov games (see e.g. 1990 games). Instead of <code>12.a4</code>, nowadays the more go-to and modern
  option is <code>12.d5.</code> So, seeing <code>12.a4</code> might have come as a bit of a surprise. </p>
  
  <p>Fast-forwarding to the key moment of the opening, in the <code>a4</code> variation white often waits out the <code>d5</code> advance until black has played <code>c5.</code> Then after <code>15...c5 16.d5</code></p>
  
  <h2>the main and key move by black is to play <code>Nd7</code> (diagram below): which concretely prepares either options of <code>c4</code> or <code>f5</code>:</h2>
  
  <p><a href="https://i.sstatic.net/aSdZdm.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/aSdZdm.jpg" alt="enter image description here"></a></p>
  
  <ul>
  <li><code>c4</code> (left diagram): with ideas of establishing either a knight or a protected advanced pawn on <code>d3</code></li>
  <li><code>f5</code> (right diagram): directly undermining the defense of the <code>d5.</code></li>
  </ul>
  
  <p><a href="https://i.sstatic.net/k211lm.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/k211lm.jpg" alt="enter image description here"></a>
  <a href="https://i.sstatic.net/VKUt7m.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/VKUt7m.jpg" alt="enter image description here"></a></p>
  
  <p>However, Kovalev played the immediate <code>c4</code> advance <strong>without</strong> the inclusion of <code>Nd7</code>, this was the <strong>main inaccuracy</strong>! The problem is black's losing a pawn in the all ensuing lines without any dynamic or positional compensation for it. Let's see some of these lines in the annotated diagram below:</p>
  
  <pre><code> [title "16.c4 without Nd7"]
   [fen ""]
   [StartPly "33"]
  
   1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Bb7 10. d4 Re8 11. Nbd2 Bf8 12. a4 h6 13. Bc2 exd4 14. cxd4 Nb4 15. Bb1 c5 16. d5 c4 17. Nd4 {b5 pawn is attacked twice now} Nd7 {this is what happened in the game, but Nd7 here is too late} (17...Qb6 {an attempt to directly defend the pawn, but the queen ends up being completely misplaced as we'll see and too far away from the kingside.} 18. N2f3 {defending the d4 knight and preparing Be3} g6 19. Be3 Qc7 {side-stepping the discovery} (19...bxa4 {just for the sake of discussion, let's see how black loses by force if they do not side step the discovered threat and take on a4 instead} 20. Ne6 Qb5 21. Nxf8 Rxf8 22. Qd4 {and white's kingside attack is too much to parry as the king on g8 is defenceless}) 20. axb5 {winning the b5 pawn if black recaptures, so only chance is to take on e4 instead} Nxe4 21. Ne6 {and white's nearly winning already as black's position is collapsing after fxe6 Bxe4. Ne6 is a thematic move in these structures with the pawn on d5.} ) 18. axb5 axb5 19. Rxa8 Bxa8 20. Nxb5 Qb8 21. Na3 {c4 is falling next, as happened in the game} Nd3 22. Re3 Nxc1 23. Qxc1 g6 24. Naxc4 {rest of the game is not included here}
  </code></pre>
  
  <p>In contrast, here's how the variation usually continues when <code>c4</code> is prefaced by <code>Nd7</code>:</p>
  
  <pre><code> [title "Correct move order: Nd7 before c4, actually setting up Nd3"]
   [fen "r2qrbk1/1b3pp1/p2p1n1p/1ppP4/Pn2P3/5N1P/1P1N1PP1/RBBQR1K1 b - - 0 16"]
   [startflipped "0"]
  
   1...Nd7 {black entertains both options of f5 and c4 after Nd7} 2. Ra3 {These are nuanced moves which were specially polished in Kasparov-Karpov games of 90's. Ra3 is a multi-faceted move, moving the rook to a protected square so that axb5 axb5 lines do not force white to exchange rooks at once, moreover activates the rook along the 3rd row both additional coverage of d3 square and potential rook swings to kingside} c4 3. axb5 axb5 4. Nd4 Rxa3 5. bxa3 Nd3 {black appears to be losing a pawn nonetheless, however as demonstrated by Morozevich among others, black is in fact able to maintain the awkwardly advanced d3 pawn with Nc5 which gives black sufficient dynamic compensation for the pawn} 6. Bxd3 cxd3 7. Re3 Nc5 {and black is well on time with Nc5 as opposed to what transpired in the game where black delayed Nd7 to after c4!} 8. Nxb5 {not white's best choice} (8. Bb2 {white's best choice here is not to take the pawn as that gives black too much counter-play.}) Qa5 9. Nd4 Qc3 {and Qa1 threats are constantly in the air. Additionally, the knight on d2 is bound to the defense of the e4 pawn. Black is clearly better.}
  </code></pre>
  
  <p>It would go beyond the scope of this post to exhaust all possible sub variations both with and without <code>Nd7</code>, however I hope the above discussion and lines clarify the importance of the inclusion of <code>Nd7</code> (and the playability of the ensuing lines) in contrast to the inaccurate early <code>c4</code> without <code>Nd7</code> as happened in the game.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-01-13T16:57:56.257Z
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Answers.LastEditDate: 2020-01-14T08:40:20.163Z
Answers.UserDisplayName: Ellie
Answers.Body: <p>We can only imagine that he somehow had a human moment, and messed up.</p>
  
  <p>The normal move instead of 16...c4 is 16...Nd7 17.Ra3 and only then 17...c4.</p>
  
  <p>The way it was played, it was almost the forced loss of a pawn. He had the option of Qb6, but it left him with a miserable position anyway.</p>
  
  <pre><code> [FEN "r2qrbk1/1b3pp1/p2p1n1p/1ppP4/Pn2P3/5N1P/1P1N1PP1/RBBQR1K1 b - - 0 1"]
  
  1... c4?  (1... Nd7 {Preparing f5 immediately so that the Nb4 can come back to d5 after any trade of pawns.} 2. Ra3 c4 3. axb5 axb5 4. Nd4 Qb6 {And black is doing well.}) 2. Nd4 (2. Nf1 {The computer thinks this is even better since the Nb2 is susceptible to Bd2 forcing Nd3 which will lead to the loss of a pawn.}) 2... Qb6 3. N2f3 bxa4 (3... g6 4. Be3 {And this is very uncomfortable for black due to the weakness on b5, and the unfortunate queen.}) 4. Rxa4 a5 {And black's queenside is wrecked.}
  </code></pre>
  
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Answers.Text: Thank you Brian for the FEN correction. I was actually making progress, but you saved me.
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Body: <p>In the first round of the ongoing Wijk aan zee Masters tournament, <a href="https://chess24.com/en/watch/live-tournaments/tata-steel-masters-2020/1/1/7" rel="noreferrer">Firouzja won vs Kovalev</a>. Apparently, right out of the opening white had gained a winning edge. In particular, somewhere around 16...c4 it seems to be where black went somehow wrong (computers also favoring white there). But from the opening point of view, </p>
  
  <ul>
  <li>how can Kovalev's 16...c4 be so bad that white has already a substantial edge? Was this a mix-up in the opening variations? First glance, it seems b5 is indeed weak as c4 frees d4 square for the knight, but can we not hold on to the b5 pawn differently? for example with Qb6? </li>
  </ul>
  
  <p>Position at move 16:</p>
  
  <pre><code> [title "Firouzja vs Kovalev 16...c4"]
   [fen "r2qrbk1/1b3pp1/p2p1n1p/1p1P4/Pnp1P3/5N1P/1P1N1PP1/RBBQR1K1 w - - 0 17"]
  </code></pre>
  
Tags: <opening><positional-play><ruy-lopez>
Title: Firouzja vs Kovalev: what went wrong for black in the opening?
ThreadText: # Firouzja vs Kovalev: what went wrong for black in the opening?
  
  (Asked by: username_0 on 2020-01-13)
  
  In the first round of the ongoing Wijk aan zee Masters tournament, [Firouzja won vs Kovalev](https://chess24.com/en/watch/live-tournaments/tata-steel-masters-2020/1/1/7). Apparently, right out of the opening white had gained a winning edge. In particular, somewhere around 16...c4 it seems to be where black went somehow wrong (computers also favoring white there). But from the opening point of view,
  
  * how can Kovalev's 16...c4 be so bad that white has already a substantial edge? Was this a mix-up in the opening variations? First glance, it seems b5 is indeed weak as c4 frees d4 square for the knight, but can we not hold on to the b5 pawn differently? for example with Qb6?
  
  Position at move 16:
  
  ```
   [title "Firouzja vs Kovalev 16...c4"]
   [fen "r2qrbk1/1b3pp1/p2p1n1p/1p1P4/Pnp1P3/5N1P/1P1N1PP1/RBBQR1K1 w - - 0 17"]
  
  ```
  
  **Tags:** opening, positional-play, ruy-lopez
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2020-01-13. Score: 7
  
  ## tl;dr: Wrong move order by black in the opening: the c4 advance must be prefaced with Nd7 in the played Zaitsev variation.
  
  That said, and although your hunch about the early `c4` is correct, I'm afraid there's no simple answer that immediately explains why the immediate `c4` is bad and why `Nd7` is so crucial, since the [Ruy Lopez](https://en.wikipedia.org/wiki/Ruy_Lopez) and the Zaitsev are highly theoretical openings and thus, all about nuances and concrete assessments.
  
  *In any case, here's an attempt to answer it in a simplified manner.*
  
  **Bit of context first:** the game started out as a classical Ruy Lopez which then transitioned into [the Zaitsev variation](https://en.wikipedia.org/wiki/Ruy_Lopez#Zaitsev_Variation:_9.h3_Bb7). Then in particular after `11...Bf8`, Firouzja opted for the older system with `12.a4` which is
  a variation rich in theory dating specially back to the Kasparov-Karpov games (see e.g. 1990 games). Instead of `12.a4`, nowadays the more go-to and modern
  option is `12.d5.` So, seeing `12.a4` might have come as a bit of a surprise.
  
  Fast-forwarding to the key moment of the opening, in the `a4` variation white often waits out the `d5` advance until black has played `c5.` Then after `15...c5 16.d5`
  
  ## the main and key move by black is to play `Nd7` (diagram below): which concretely prepares either options of `c4` or `f5`:
  
  [![enter image description here](https://i.sstatic.net/aSdZdm.jpg)](https://i.sstatic.net/aSdZdm.jpg)
  
  * `c4` (left diagram): with ideas of establishing either a knight or a protected advanced pawn on `d3`
  * `f5` (right diagram): directly undermining the defense of the `d5.`
  
  [![enter image description here](https://i.sstatic.net/k211lm.jpg)](https://i.sstatic.net/k211lm.jpg)
  [![enter image description here](https://i.sstatic.net/VKUt7m.jpg)](https://i.sstatic.net/VKUt7m.jpg)
  
  However, Kovalev played the immediate `c4` advance **without** the inclusion of `Nd7`, this was the **main inaccuracy**! The problem is black's losing a pawn in the all ensuing lines without any dynamic or positional compensation for it. Let's see some of these lines in the annotated diagram below:
  
  ```
   [title "16.c4 without Nd7"]
   [fen ""]
   [StartPly "33"]
  
   1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Bb7 10. d4 Re8 11. Nbd2 Bf8 12. a4 h6 13. Bc2 exd4 14. cxd4 Nb4 15. Bb1 c5 16. d5 c4 17. Nd4 {b5 pawn is attacked twice now} Nd7 {this is what happened in the game, but Nd7 here is too late} (17...Qb6 {an attempt to directly defend the pawn, but the queen ends up being completely misplaced as we'll see and too far away from the kingside.} 18. N2f3 {defending the d4 knight and preparing Be3} g6 19. Be3 Qc7 {side-stepping the discovery} (19...bxa4 {just for the sake of discussion, let's see how black loses by force if they do not side step the discovered threat and take on a4 instead} 20. Ne6 Qb5 21. Nxf8 Rxf8 22. Qd4 {and white's kingside attack is too much to parry as the king on g8 is defenceless}) 20. axb5 {winning the b5 pawn if black recaptures, so only chance is to take on e4 instead} Nxe4 21. Ne6 {and white's nearly winning already as black's position is collapsing after fxe6 Bxe4. Ne6 is a thematic move in these structures with the pawn on d5.} ) 18. axb5 axb5 19. Rxa8 Bxa8 20. Nxb5 Qb8 21. Na3 {c4 is falling next, as happened in the game} Nd3 22. Re3 Nxc1 23. Qxc1 g6 24. Naxc4 {rest of the game is not included here}
  
  ```
  
  In contrast, here's how the variation usually continues when `c4` is prefaced by `Nd7`:
  
  ```
   [title "Correct move order: Nd7 before c4, actually setting up Nd3"]
   [fen "r2qrbk1/1b3pp1/p2p1n1p/1ppP4/Pn2P3/5N1P/1P1N1PP1/RBBQR1K1 b - - 0 16"]
   [startflipped "0"]
  
   1...Nd7 {black entertains both options of f5 and c4 after Nd7} 2. Ra3 {These are nuanced moves which were specially polished in Kasparov-Karpov games of 90's. Ra3 is a multi-faceted move, moving the rook to a protected square so that axb5 axb5 lines do not force white to exchange rooks at once, moreover activates the rook along the 3rd row both additional coverage of d3 square and potential rook swings to kingside} c4 3. axb5 axb5 4. Nd4 Rxa3 5. bxa3 Nd3 {black appears to be losing a pawn nonetheless, however as demonstrated by Morozevich among others, black is in fact able to maintain the awkwardly advanced d3 pawn with Nc5 which gives black sufficient dynamic compensation for the pawn} 6. Bxd3 cxd3 7. Re3 Nc5 {and black is well on time with Nc5 as opposed to what transpired in the game where black delayed Nd7 to after c4!} 8. Nxb5 {not white's best choice} (8. Bb2 {white's best choice here is not to take the pawn as that gives black too much counter-play.}) Qa5 9. Nd4 Qc3 {and Qa1 threats are constantly in the air. Additionally, the knight on d2 is bound to the defense of the e4 pawn. Black is clearly better.}
  
  ```
  
  It would go beyond the scope of this post to exhaust all possible sub variations both with and without `Nd7`, however I hope the above discussion and lines clarify the importance of the inclusion of `Nd7` (and the playability of the ensuing lines) in contrast to the inaccurate early `c4` without `Nd7` as happened in the game.
  
  
  ---
  
  ### Answer by username_2 on 2020-01-13. Score: 4
  
  We can only imagine that he somehow had a human moment, and messed up.
  
  The normal move instead of 16...c4 is 16...Nd7 17.Ra3 and only then 17...c4.
  
  The way it was played, it was almost the forced loss of a pawn. He had the option of Qb6, but it left him with a miserable position anyway.
  
  ```
   [FEN "r2qrbk1/1b3pp1/p2p1n1p/1ppP4/Pn2P3/5N1P/1P1N1PP1/RBBQR1K1 b - - 0 1"]
  
  1... c4?  (1... Nd7 {Preparing f5 immediately so that the Nb4 can come back to d5 after any trade of pawns.} 2. Ra3 c4 3. axb5 axb5 4. Nd4 Qb6 {And black is doing well.}) 2. Nd4 (2. Nf1 {The computer thinks this is even better since the Nb2 is susceptible to Bd2 forcing Nd3 which will lead to the loss of a pawn.}) 2... Qb6 3. N2f3 bxa4 (3... g6 4. Be3 {And this is very uncomfortable for black due to the weakness on b5, and the unfortunate queen.}) 4. Rxa4 a5 {And black's queenside is wrecked.}
  
  ```
  
  > **Comments:**
  > **username_2**: Thank you Brian for the FEN correction. I was actually making progress, but you saved me.  
  
  ---
  
  