user1758: For much of today's Anand-Carlsen game, white seemed to have a powerful mating attack. But from the analyses I've seen, there was never a point where it was clear that black would not be able to defend against best play. Was there any point in the game at which, with best play on white's part, all lines lead to a win?
[FEN ""]
[Event "WCh 2013"]
[Site "Chennai IND"]
[Date "2013.11.21"]
[Round "9"]
[White "Anand, Viswanathan"]
[Black "Carlsen, Magnus"]
[Result "0-1"]
[ECO "E25"]
[WhiteElo "2775"]
[BlackElo "2870"]
[PlyCount "56"]
[EventDate "2013.11.09"]

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 d5 5. a3 Bxc3+ 6. bxc3 c5 7. cxd5 exd5 8.
e3 c4 9. Ne2 Nc6 10. g4 O-O 11. Bg2 Na5 12. O-O Nb3 13. Ra2 b5 14. Ng3 a5 15.
g5 Ne8 16. e4 Nxc1 17. Qxc1 Ra6 18. e5 Nc7 19. f4 b4 20. axb4 axb4 21. Rxa6
Nxa6 22. f5 b3 23. Qf4 Nc7 24. f6 g6 25. Qh4 Ne8 26. Qh6 b2 27. Rf4 b1=Q+ 28.
Nf1 Qe1 0-1


user2857: I ran this position through an analysis engine, which assesses it as a win for black after 
28. Bf1 Qd1 29. Rh4 Qh5 30. Rxh5? gxh5 31. Nxh5 Qa5 32. Ng7 Qxc3 33. Nxe8 Qxd4+ 34. Kg2 35. Qg6.
But it gives Black only a slight edge after 30. Nxh5 (instead of Rxh5) gxh5 31. Rxh5 Bf5 32. Bh3 Bg6 33. e6 Nxf6 34. gxf6 Qxf6. 

user1968: How about 28 Kf2? Answer either 28 ... Qc2+ or 28 ... Qd1 with 29. Ne2. 

user1824: The game was ambiguous until move 28, there is no clear way to win but as you mentioned white has the attacking form.
Let see the game from move 18.e5
2bqnrk1/5ppp/r7/pp1p2P1/2pPP3/P1P2PN1/R5BP/2Q2RK1 w - - 1 18

White is attacking on king's side as Kasparov mentioned he could play 18.Rb2 to avoid black to make a passed pawn and keep pressure in both king and queen sides. But white decided to complicate the game.
Another move which leads many people criticize Anand was move 20.axb4
2bq1rk1/2n2ppp/r7/p2pP1P1/1ppP1P2/P1P3N1/R5BP/2Q2RK1 w - - 0 20

1.f5 b3 2.Raf2

Some GMs and also engines prefer to push the pawn to f5 and continue attacking just in king's side. White's 20.axb4 made a passed pawn for black on square b3 (two moves to promote) and black got counter play.
Before move 28 white had attacking chances and a draw at least. But white made a blunder 28.Nf1??, if 28.Bf1 was played, then the game can continue in this way:
2bqnrk1/5p1p/5PpQ/3pP1P1/2pP1R2/2P3N1/6BP/1q4K1 w - - 1 28

1. Bf1 Qd1 2. Rh4 Qh5 3. Nxh5 gxh5 4. Rxh5 Bf5

The game is almost a draw with some minor advantages for black. It's ambiguous.
But white played 28.Nf1?? and black put his queen on e1 to capture the white's rook on h4 -- a big material advantage for black.

1758: <p>For much of today's Anand-Carlsen game, white seemed to have a powerful mating attack. But from the analyses I've seen, there was never a point where it was clear that black would not be able to defend against best play. Was there any point in the game at which, with best play on white's part, all lines lead to a win?</p>

<pre><code>[FEN ""]
[Event "WCh 2013"]
[Site "Chennai IND"]
[Date "2013.11.21"]
[Round "9"]
[White "Anand, Viswanathan"]
[Black "Carlsen, Magnus"]
[Result "0-1"]
[ECO "E25"]
[WhiteElo "2775"]
[BlackElo "2870"]
[PlyCount "56"]
[EventDate "2013.11.09"]

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 d5 5. a3 Bxc3+ 6. bxc3 c5 7. cxd5 exd5 8.
e3 c4 9. Ne2 Nc6 10. g4 O-O 11. Bg2 Na5 12. O-O Nb3 13. Ra2 b5 14. Ng3 a5 15.
g5 Ne8 16. e4 Nxc1 17. Qxc1 Ra6 18. e5 Nc7 19. f4 b4 20. axb4 axb4 21. Rxa6
Nxa6 22. f5 b3 23. Qf4 Nc7 24. f6 g6 25. Qh4 Ne8 26. Qh6 b2 27. Rf4 b1=Q+ 28.
Nf1 Qe1 0-1
</code></pre>
 2857: <p>I ran this position through an analysis engine, which assesses it as a win for black after 
28. Bf1 Qd1 29. Rh4 Qh5 30. Rxh5? gxh5 31. Nxh5 Qa5 32. Ng7 Qxc3 33. Nxe8 Qxd4+ 34. Kg2 35. Qg6.</p>

<p>But it gives Black only a slight edge after 30. Nxh5 (instead of Rxh5) gxh5 31. Rxh5 Bf5 32. Bh3 Bg6 33. e6 Nxf6 34. gxf6 Qxf6. </p>
 1968: <p>How about 28 Kf2? Answer either 28 ... Qc2+ or 28 ... Qd1 with 29. Ne2. </p>
 1824: <p>The game was ambiguous until move 28, there is no clear way to win but as you mentioned white has the attacking form.</p>

<p>Let see the game from move <code>18.e5</code></p>

<pre><code>2bqnrk1/5ppp/r7/pp1p2P1/2pPP3/P1P2PN1/R5BP/2Q2RK1 w - - 1 18
</code></pre>

<p>White is attacking on king's side as Kasparov mentioned he could play <code>18.Rb2</code> to avoid black to make a passed pawn and keep pressure in both king and queen sides. But white decided to complicate the game.</p>

<p>Another move which leads many people criticize Anand was move <code>20.axb4</code></p>

<pre><code>2bq1rk1/2n2ppp/r7/p2pP1P1/1ppP1P2/P1P3N1/R5BP/2Q2RK1 w - - 0 20

1.f5 b3 2.Raf2
</code></pre>

<p>Some GMs and also engines prefer to push the pawn to <code>f5</code> and continue attacking just in king's side. White's <code>20.axb4</code> made a passed pawn for black on square <code>b3</code> (two moves to promote) and black got counter play.</p>

<p>Before move 28 white had attacking chances and a draw at least. But white made a blunder <code>28.Nf1??</code>, if <code>28.Bf1</code> was played, then the game can continue in this way:</p>

<pre><code>2bqnrk1/5p1p/5PpQ/3pP1P1/2pP1R2/2P3N1/6BP/1q4K1 w - - 1 28

1. Bf1 Qd1 2. Rh4 Qh5 3. Nxh5 gxh5 4. Rxh5 Bf5
</code></pre>

<p>The game is almost a draw with some minor advantages for black. It's ambiguous.</p>

<p>But white played <code>28.Nf1??</code> and black put his queen on <code>e1</code> to capture the white's rook on <code>h4</code> -- a big material advantage for black.</p>
