The London Chess Classic, the third and final event of the Grand Chess Tour, is now over halfway completed as we enter tomorrow’s day of rest. Just four more rounds of play remain before a champion is crowned, and we still have very little indication who that will ultimately be. Before we look at the current state of affairs, let’s look back at how we got here.
The inaugural Grand Chess Tour is a series of three major chess tournaments, bringing nine of the best players in the world (plus one additional wild card participant in each event) together three separate times through the year. In each tournament, players accumulate points based on their placement in the final standings, and in the end the Grand Chess Tour champion is the player who accumulates the most combined points.
We began in Norway where world champion Magnus Carlsen, the highest rated player in the world, had an opportunity to harness home-nation advantage in the first leg of the tour. Our statistical model saw Carlsen as the prohibitive favorite to ultimately win the tour; while he had less than a 50% chance of winning any given tournament, his huge rating advantage suggested that it was extremely unlikely for him to ever finish too far behind first place, and figured that he should consistently earn high point totals in all three events, and that this would likely carry him to first place in the ultimate tour standings. Before the first games were played, our model gave him an estimated 68% chance of winning the tour, with just a 32% chance that one of the other eight contenders could outpace him.
That changed faster than we could have imagined. Carlsen lost his first game against Veselin Topalov. Then lost again in round two to Fabiano Caruana. After finally holding at least a draw in the third round, Carlsen was defeated yet again in his fourth game by Viswanathan Anand! The disastrous start plunged Carlsen’s odds of ultimate tour victory to under 17%, while Topalov (with three wins and a draw to that point) emerged as the new favorite at 30%.
Topalov did indeed maintain his momentum and emerge as the clear victor at Norway Chess. Anand finished in second place. With the first of three legs completed, here were how the standings looked (excluding wild card Jon Ludvig Hammer, who finished in last place and earned the minimum 1 point), and how our model projected each player’s updated odds at that point, based on their results so far and using their updated ratings to project the remaining events:
Carlsen’s shocking seventh place finish didn’t eliminate him from ultimate contention, as his (not quite as) high rating still suggested he had the potential to come back. However the world champion had a lot of work to do if he wanted to make that happen, and he was definitely no longer the front runner going into leg two of the tour: the Sinquefield Cup.
He didn’t have to wait for his opportunity, as Carlsen had the white pieces in the first round against new favorite Topalov, and a chance to avenge his first round loss from the prior event. However fate took a different twist, and Topalov defeated the world’s top player once again! With that, our model calculated that Topalov’s odds of eventually winning the entire tour had skyrocketed to over 80% while Carlsen’s chances were whittled down to just over 5%.
By round four, Topalov’s odds had risen to almost 82%, as he led the event with 3 points out of 4. However his stranglehold on first place faded when he lost his next two games. Three draws to close things out, along with poor tiebreaks, left him in 7th place this time around (the same fate that Carlsen had suffered in Norway) while Levon Aronian (who had finished ninth in Norway) emerged as the victor. Carlsen rebounded to finish second, while Hikaru Nakamura finished in third place for the second consecutive event. When all the points were counted, Topalov was still in first place overall, but by the slimmest of margins over second place Nakamura, and the standings were drastically bunched – meaning the final leg could easily prove to be winner take all.
Carlsen’s elite rating and strong recovery over the second half of the Sinquefield Cup was enough to overcome his gap in the standings, and he was once again the slight favorite to win the tour in the end, but Topalov and Nakamura were right there in contention, and several others were far from eliminated. This is where we stood the last time we published an article on the Grand Chess Tour three months ago:
In order to illustrate how volatile the standings and projections were over the course of these first two events, let us look at each player’s lowest point. The favorite here was Magnus Carlsen, but after his round one loss at the Sinquefield Cup, his odds had been just 3.4% according to our model. The second most likely victor at this point was Topalov, but when the tour first began our model gave him just a 4.4% chance to win it all. Third most likely to win the tour was Nakamura, to whom our model gave a mere 4.7% chance after the fourth round was completed in St. Louis. And these three’s nadirs weren’t even as bad as the rest of the field! Each of the other six players had seen their odds dip under 2.5% at some point during one of the first two events.
Essentially every player had, at one point, looked to have less than a one in twenty chance of winning the tour. Of course there still had to be a winner, so someone was guaranteed to overcome incredibly steep odds – we just didn’t yet know who!
In the intervening months several major tournaments took place, and everyone in the field had numerous opportunities to play chess. Ratings fluctuated, and the odds shifted with them. By the time lots were drawn and our model was updated to include the actual pairings of the London Chess Classic, Topalov’s rating had climbed and Carlsen’s had fallen, so the favorite changed without a Grand Chess Tour game even being played. Here were each player’s odds entering the third and final leg of the tour:
And so finally we reached the tournament that is now in progress, the London Chess Classic!
London Rounds 1-3:
While four of the games in this round ended in draws, the one decisive result carried major importance. Topalov quickly shed his role as favorite by losing his first game (and with the white pieces no less) to Anish Giri. This made Carlsen the new favorite at 26%, with Nakamura, Giri, Aronian, and Topalov all still in the mix with chances in the double digit range.
In the second round little changed as all five games were drawn, and in the third round there was once again just a single decisive game. It was again big, though, as Topalov continued to make it clear that his former 80% chances were to be in vain, losing once again to someone near the bottom of the tour standings – Maxime Vachier-Lagrave this time!
At this point Carlsen was still the favorite, but at only 24%. More to the point, the field was absolutely wide open with just six games left. Here is how the odds shook out at that point:
London Round 4:
With so many players in the mix at the top, and 13 of the first 15 games being drawn, clearly someone in the upper group was going to need a win to establish themselves as a front runner. In the fourth round there was just one decisive game, but it did indeed serve that purpose: Hikaru Nakamura defeated Viswanathan Anand.
The victory catapulted Nakamura to a 41% chance of winning the tour, but while we once again had a leader with significantly better chances than any individual rival (Carlsen had just a 16% chance as the second most likely champion), nevertheless he remained an underdog to “the field”. Nakamura was the latest leader, but that position had thus far proven to be a revolving door. Did we finally have someone who would hold onto the spot? It was clear that he would probably need at least one more win to actually achieve victory – the model at this point gave him only a 34% chance of winning the tour if he drew his five remaining games. Sure, that was enough to be the favorite, but not convincingly. Not knowing who would pass him doesn’t change that all draws left him a 2-1 underdog.
Ignoring that speculation, here is where our model said the odds stood at that point:
London Round 5:
And so finally we come to today’s action. Again, four games out of five were drawn. And again, the one player to lose his game was the former prohibitive favorite Topalov. This time he lost to Anand (who bounced back from his round 4 loss). With that, Topalov’s odds of winning the tour are about one in 450. Extremely low, but with all the twists and turns we’ve seen so far perhaps not so low as to give up entirely.
Nakamura remains the player with the best odds, but still an underdog to the combined field. He still probably needs at least one more win to feel comfortable remaining favored. Should he falter there is no shortage of players who might potentially replace him at the top. With just four rounds of chess left to play, here is where we stand:
To help visualize how much the odds have fluctuated from game to game, through the first two and a half tournaments, here is a graph of each player’s round by round win probabilities:
What plot twists remain in store? Will Nakamura win again and cruise to victory? Or will someone else surpass him in the end? We can spend tomorrow’s rest day speculating on just that before the action resumes on Thursday. And by the end of this coming weekend, we will have our answers. It sure does look to be an exciting four days of chess, with no shortage of intrigue!