World Cup Recap: Day 10 (Round 4, first game)

Today provided the most drastic swings in the expected final results of the tournament that we’ve seen so far, despite nobody actually being eliminated, as half of the eight games produced decisive results. Two of the top three seeds, Veselin Topalov and Fabiano Caruana, lost their games today and now must win tomorrow to stay alive. Having entered the day among the favorites to reach the finals, these two losses were huge blows that dramatically shifted our projections. On the other hand, two other games involving top-eight seeds were won by the favorites, and these victors (Hikaru Nakamura and Ding Liren) saw huge gains in their own chances to reach the finals as a result. They are now the front runners on their respective sides of the bracket, and there is now roughly a 15% chance that they will face each other in the finals!

Here is how much ground everyone gained or lost in their quest for a berth in the finals (and correspondingly a berth in the 2016 Candidates Tournament):

Seed	Player	Rating	New Odds of Reaching Finals	Change
2	Hikaru Nakamura (USA)	2814.6	47.6%	15.1%
8	Ding Liren (CHN)	2786.3	31.4%	15.0%
19	Shakhriyar Mamedyarov (AZE)	2743.2	11.8%	7.0%
16	Peter Svidler (RUS)	2732.2	8.3%	5.2%
5	Wesley So (USA)	2767.1	12.8%	2.1%
20	Radoslaw Wojtaszek (POL)	2741.2	6.1%	1.4%
11	Sergey Karjakin (RUS)	2766.0	14.7%	1.3%
26	Pavel Eljanov (UKR)	2743.4	7.1%	0.2%
21	Maxime Vachier-Lagrave (FRA)	2762.6	9.1%	0.1%
27	Dmitry Andreikin (RUS)	2728.4	4.1%	0.0%
4	Anish Giri (NED)	2792.8	20.5%	-1.1%
10	Dmitry Jakovenko (RUS)	2742.6	5.7%	-1.2%
24	Wei Yi (CHN)	2731.5	0.9%	-3.3%
15	Michael Adams (ENG)	2739.6	1.0%	-4.2%
3	Fabiano Caruana (USA)	2792.7	8.0%	-18.1%
1	Veselin Topalov (BUL)	2803.7	10.9%	-19.5%

So how about tomorrow? For the sake of interesting scenarios it benefits fans that all four decisive wins came with the white pieces today, as that means everyone in a must-win situation tomorrow gets to fight for their survival with the advantage of the first move. Let’s look at the eight matchups individually.

Topalov’s side of the bracket:

Topalov vs. Svidler

Peter Svidler upset the number one seed with white in the first game, and is now a 69% favorite to advance to the quarterfinals. It’s not over yet, though. Topalov is still rated 72 points higher, plus has the advantage of the white pieces tomorrow, and our model gives him a 44% chance of achieving the equalizing win he needs to stay alive. If he wins, he’s considered a little better than a 70% favorite to win the tie breaks as well. So it’s not over yet, but Svidler certainly added a lot of intrigue to the top of the bracket with his win today! The winner of this match will face the winner of Ding Liren vs. Wei Yi in the next round. The loss was bad news for Topalov’s hopes of reaching the finals, with his odds now down under 11%, from a gaudy 30% before the game. Fortunately for Veselin any World Championship aspirations he may have did not suffer as a result, since if he doesn’t reach the finals here he will still qualify for the Candidates Tournament on rating. On the other hand Kramnik and Grischuk saw their World Championship hopes shaken by today’s result, as they are relying on a finals appearance by either Topalov or Giri in order to put one of them into the Candidates Tournament on rating.

Ding vs. Wei

This clash between two Chinese stars opened with tactical fireworks in a game that could easily have gone either way, but was ultimately won by the older and more experienced player. Favored by 55 rating points and leading 1-0, Ding is now considered a 94% favorite to advance by our model. On the other hand, Wei Yi has shown remarkable resilience, and a great ability to create sharp and unclear positions in order to give himself winning chances, and tomorrow he gets to try to do so with the white pieces, which our model sees as a 17% chance for a win given the ratings. If Wei does manage to force tie breaks, a 55 point ratings favorite is expected to advance 66% of the time in the rapid/blitz format of this tournament.

These two countrymen have some history, as one would expect, having now played nine classical games against each other. With today’s win, Ding is now +2, with three wins and one loss (they’ve drawn five times). On the other hand, those results go back to a draw in 2012 when Wei was just 13 years old and rated 2371. In the last two calendar years (so going back to January 2014) they have played six times, with three draws, two wins (now) for Ding, and one win for Wei (at the Chinese championships earlier this year, an event which Wei won).

This quadrant of the bracket (Topalov, Svidler, Ding, and Wei) will produce one semifinalist, and right now Ding is the most likely, at 57%, with Svidler just under 23%, Topalov just under 18%, and Wei at just over 2%.

Giri vs. Wojtaszek

A drawn game here didn’t change the status quo too much, but slightly benefited black (as first-game draws do in this format). Wojtaszek now has a 39% chance of pulling off overcoming his 52 point rating deficit to pull the upset. Since our model rates the white pieces as worth 40 rating points, we still see Giri as slightly more likely to win tomorrow should the game be decisive, predicting a 20% chance of a Giri win, a 17% chance of a Wojtaszek win, and a 63% chance of a draw. This is not player specific though, and given Giri’s reputation I imagine some observers might argue that the odds of a draw are higher than that. If it does go to tie breaks, Giri’s rating edge is enough to generate a 65% chance of victory in that phase, according to our model. The winner of this matchup will then face either Wesley So or Maxime Vachier-Lagrave.

So vs. Vachier-Lagrave

Another of today’s draws, again we saw just a small shift in the odds, again in favor of the player who gets the white pieces tomorrow, which in this case is So. These two players are separated by a mere five rating points, and So entered the day as the smallest of favorites, at 52% to advance. With his draw today, he gained slightly and is now a 57% favorite to move on. Thanks to having the white pieces, our model gives So a 28% chance of winning to end things immediately, and just a 16% chance of being knocked out with a loss. The rest of the time the match would go to tie breaks where So’s five extra rating points earn him a 51% chance of advancing – basically a coin flip.

In this quadrant of the bracket, where noone yet has an scoreboard edge, the odds of earning the one available semifinal spot are simply an exercise in “sort by ratings”, with Giri the favorite at 37%, So at 27%, MVL at 20%, and Wojtaszek at 16%. If he gets that far, Giri would be a small favorite over Ding in the semis, but Ding would be favored over the other three, and so Ding is the most likely finalist in this half, but at only 31%. Things are pretty wide open, with seven of the eight players still having at least a 6% chance (sorry Wei Yi).

Nakamura’s side of the bracket:

Nakamura vs. Adams

Given that Nakamura is a 75 point ratings favorite and also holds a 1-0 lead, this is not a good spot for Adams. Our model gives him less than a 5% chance of reaching the quarterfinals at this point, down from 27.5% before today’s game. Even with the white pieces, we only expect a player surrendering that many rating points to win 16% of the time, and should he manage to do so he would have less than a 30% chance of winning the tie breaks – and that doesn’t even account for the fact that his specific opponent is the strongest in the field in rapid and blitz chess, and is almost certainly underrated by the model in tie break scenarios. It would be a complete shocker, at this point, if Nakamura somehow failed to reach the quarterfinals. Nakamura (or if a shocker occurs, perhaps Adams) will face the winner of Eljanov/Jakovenko in the next round.

Jakovenko vs. Eljanov

Jakovenko was the favorite by seed, but ratings said these two were exactly equal. Today’s result said the same, as the game was drawn. While Eljanov saw the end of his streak of perfection (he had won his first six World Cup games, before finally being held to a draw for the first time today) he still gains from the rule that draws with black are good, and is now a small 56% favorite to advance thanks to the benefit of the white pieces in tomorrow’s game. We see him winning 27% of the time, and losing 16% of the time. Otherwise it will go to tie breaks where the odds will return to 50/50.

In this quadrant, Nakamura is a commanding ratings favorite over the other three, and the only player with a win to his credit so far this round. As such he is a strong 69% favorite to reach the semifinals, with Eljanov at 16%, Jakovenko 13%, and Adams just 2%.

Caruana vs. Mamedyarov

Today’s other major upset was the last remaining player from the host country knocking off the #3 seed. Mamedyarov surrenders 50 rating points, but his 1-0 lead makes him a 75% favorite to advance. Like the other players who lost a game today, though, Caruana gets the white pieces tomorrow in his battle for survival. His effective 90 point rating advantage (including the value of the white pieces) gives him a 39% chance to win and force tie breaks, where he would be expected to win about 65% of the time. If he manages to do so, he would face either Karjakin or Andreikin in the quarterfinals. However his 1-0 deficit is a major hurdle that, as with Topalov, means his chances of reaching the final took a huge hit today. He now has just an 8% chance of reaching the final, down from 26%. Of course like Topalov this isn’t a huge problem for him, as he will be in the Candidates Tournament either way having already won the Grand Prix. It’s more of a problem for Jakovenko, who needs one of Caruana, Nakamura, or himself to win in order to reach the Candidates Tournament. Success for any of the other five players in the bracket (Mamedyarov in this case) hurts Jakovenko’s World Championship hopes.

Karjakin vs. Andreikin

Another draw, another small gain for the black player, which here was Karjakin, also the favorite by rating. Between his 38 point rating edge and the white pieces tomorrow, Karjakin is now up to a 67% chance of moving on to the next round. In particular he has a 36% chance to advance immediately with a win tomorrow, and just a 14% chance of being eliminated with a loss tomorrow. If we see another draw instead, Karjakin would rate as a 61% favorite in the tie breaks.

In this quadrant, Mamedyarov’s status as the only player with a win under his belt benefits him, of course, but his relatively low rating works against him and he’s actually only the second most semifinalist in the group. Karjakin is 36%, Mamedyarov 34.5%, Caruana 16%, and Andreikin 13.5%. With no clear favorite in this group, when the opposing group does have a clear leader (who’s also the highest rated player in the field), that leader is of course the most likely finalist. Nakamura is very close to becoming the first player tabbed as a true favorite (over the entire rest of his bracket combined) to reach the finals, at almost 48%. Only two other players, Karjakin and Mamedyarov, have better than a 10% chance of earning that spot.