1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 e6 5.Bg5 h6
Nakamura paused for a while here, wondering whether to wimp out of the sharp lines by playing 6.Bxf6 but then took a deep breath and  abandoned his c pawn for good...
6.Bh4 dxc4 7.e4 g5 8.Bg3 b5 9.Ne5
Nakamura has mostly used the more popular moves 9.Be2 and 9.e5 in this position but 9.Ne5 would not have come as a surprise to Anand since on his most recent outing in this line, against Gelfand at the 2010 Olympiad, Nakamura had chosen 9.Ne5.
9...Nbd7!?

The first real shock. Though he had never used the regulation move 9...Bb7, in the past Anand had relied on 9...h5, though once trying 9...Bg7.
10.Nxc6!
Until this game, grabbing the pawn had scored precisely 0% for White, including a bad loss by Anand's second Rustam Kasimdzhanov against Gelfand.
10...Qb6 11.d5 Bb7 12.a4 a6 1.23 13.Be2 Bxc6
Anand played this quickly while Nakamura was starting to burn up time. (Gelfand had won with 13...Bg7, though 14.0-0 (instead of Kasimdzhanov's 14.dxe6) 0-0 15.Bf3 would have been quite unclear.
14.dxc6 Qxc6 15.axb5 axb5 16.Rxa8+ Qxa8 1.21 17.0-0 0.50 Qc6 0.39


Suddenly Anand's time advantage disappeared with one 40 minute think on this move. Anand explained that he had prepared this line some time ago (probably before his 2008 world title match against Vladimir Kramnik) and could only remember most, not all of his analysis. He bemoaned that it might have been better to have known  nothing at all!
18.e5! 0.40 Nd5 19.Nxd5 Qxd5 20.Qa1! 0.34 Bg7 0.28
20...Qb7 was the key alternative. Anand has seen that he will eventually be losing a piece by playing this way but hopes to have enough pawns to survive. However, that Black should already be grovelling, is a testament to Nakamura's precise opening play.
21.Rd1 Qc5 22.Qa8+ Ke7 23.Qb7 Rd8 24.Bf3 Bxe5 25.Bxe5?


Played very quickly by Nakamura and soon regretted. "I had worked out 5 moves before that 25.Bc6! doesn't work because of  25...Bd4 but I completely missed 26.Bc7!," admitted Nakamura. "If he plays 25...Bxg3 I saw that I was completely winning after 26.hxg3." Anand was not so certain, though accepting that 26...b4 27.Rxd7+ Rxd7 28.Qxd7+ Kf6 29.Ba4! would leave him with a long difficult defence ahead. (Computer analysis suggested that Black might just be able to survive with the decidedly non-human 25.Bc6 Kf6 26.Rxd7 Rxd7 27.Bxd7 Bxb2!!?, allowing 28.Be8 which can be met by 28...Qe7 29.Qxb5 Bd4, ready to answer 30.Qxc4 with 30...Bxf2+ when the resulting piece up ending with pawns only on one flank possibly cannot be won by White.)
25...Qxe5 26.Bc6 0.25 Kf6! 0.19 27.Bxd7 0.24 Qxb2 0.17 28.Rf1!? 0.12
An ingenious winning try. The back rank threats and the d file pin  prevent White from utilising his extra piece and 28.h4 Qe5 is safe enough for Black.
28...c3 0.11 29.Qc7 Ra8 09.57
Anand was not interested in investigating 29...Rxd7!? 30.Qxd7 c2 31.Qd2 b4 32.f4 "when 32...g4 33.f5 looks dangerous for Black because h6 is hanging," said Nakamura. "However I thought Black might be OK after 32...Kg6!," he added and this seems to be true.
30.Bxe6! 4.19


The slightest look of fear appeared on Anand's face when Nakamura played this move but he recovered his composure quickly enough.
30...fxe6 31.f4 Ra1! 4.52
By now Anand's poker face had returned and he used much of the five minutes he spent on this move gazing into space. "I think I could also have played 31...g4!?," Anand explained later, "and on  32.Qe5+ Ke7 33.f5 I have 33...Ra1, followed by running my king to the queenside. However 31...Ra1 seemed a safer option - well, not exactly safe but safe enough. I didn't see any win - with a lone queen I thought there is no way you can mate - though I was a bit worried."
32.fxg5+ Kxg5 33.Qg7+ 2.12 Kh5
Now it was Nakamura's turn to show his emotions as his clock ticked down; a mixture of disappointment and disgust with himself for throwing away such a great chance.
34.Qf7+ 1.37 34...Kg5 35.Qf6+
"I saw some line where you could play h4+ and get your queen to g6," said Anand, "but even then when you play Kh2 I have Rxf1 and g3 isn't mate because the g pawn is pinned."
35...Kh5 36.Qf7+ Kg5 37.Qg7+ Kh5 38.Qf7+


and the players shook hands on a draw six seconds before Nakamura's clock ticked down to zero.
½-½ 

"It is nice to get such a great position but in the end it is the result that matters," said a disappointed Nakamura after the game. "I can do better than this."

There will be three more rounds of the Grand Slam Final in Sao Paulo before the action moves to Bilbao, Spain for the second half.

For the players, a four day adjustment after an intercontinental flight will be tough, with press conference questions likely to concentrate on whether jet-lag is hurting the quality of the play (which has been extremely high so far in Sao Paulo).  

However if Alyssa Campanella goes on from her Thursday commitment at Sprinkles Bakery in Beverley Hills to a promotion in Bilbao next week, the rumour mill will keep spinning.

Sao Paulo Grand Slam Final
Leading scores after 2 rounds (soccer scoring system):
=1.Aronian(Arm), Ivanchuk(Ukr) 4
=3.Nakamura(USA), Anand(Ind), Carlsen(Nor) 2;
6.Vallejo(Spa) 0

Watch live games starting at 2 PM EST for the Sao Paulo leg on the official website or the Internet Chess Club. During the second leg in Bilbao, Spain, look for another exclusive CLO report by Macauley Peterson.