Sinquefield Cup Recap: All Eyes On London!

The final round of the Sinquefield Cup saw just one decisive game, and no big surprises. Aronian easily held a draw to clinch his victory. In that sense the game results had relatively little impact on player’s long term chances to win the Grand Chess Tour (although Nakamura of course gained a fair amount of ground with his win over Grischuk). After the games were completed, though, something did happen that had significant impact on the Grand Chess Tour odds: tie breaks were calculated.

As I lamented during Norway Chess, I have not yet found a good way to build proper tie breaks into my simulation model. I’m still using a version of the model I originally designed for the Grand Prix, where in the case of a tie for a given spot, points were distributed evenly among all tied players. However the Grand Chess Tour uses tie breaks and assigns whole point values to each individual instead. In the case of a four way tie for second place, as we had in this event, that makes a big difference!

A four way tie was relatively likely as we entered the last round. Any time it happened in a given simulation, the model assigned 7.75 GCT points to each player in the group. However in reality those four players were going to get 10, 8, 7, and 6 points, based on their tie breaks. As it turned out this scenario did come to pass, and the 10 points for second place went to Magnus Carlsen! The 6 points for fifth place went to Anish Giri. This means that our model now shows Carlsen as having much improved odds of winning the tour as compared to our round 8 predictions – not because he gained ground in the standings but because his tie breaks were strong. Giri, similarly, suffers a drop in his odds. Meanwhile Topalov, who after round 8 we still had as a strong favorite to win the tour, came out on the short end of his own tie break. He tied with Grischuk for sixth place, but earned seventh place points (4), where the model would have given him 4.5 points towards the standings any time it simulated this actual scenario.

Carlsen gaining ground from tie breaks, while Topalov lost ground, meant a big shift. The model now views Carlsen as the favorite to win the Grand Chess Tour!

Here are everyone’s odds of winning the Grand Chess Tour now, and where they were before each of the two legs that have been played so far began:

Player Pre-Norway Pre-Sinquefield Now
Magnus Carlsen 68.1% 13.0% 29.3%
Veselin Topalov 4.4% 42.2% 26.5%
Hikaru Nakamura 6.9% 13.0% 21.7%
Levon Aronian 2.3% 0.2% 8.7%
Anish Giri 2.4% 4.5% 6.2%
Viswanathan Anand 7.1% 21.3% 5.8%
Maxime Vachier-Lagrave 0.2% 0.2% 1.4%
Fabiano Caruana 6.3% 5.3% 0.3%
Alexander Grischuk 2.4% 0.3% 0.0%

The most important takeaway here is that the final leg of the tour, which will be played in London in December, will decide everything! We enter that last stretch with three players very close at the top, as Carlsen, Topalov, and Nakamura all have between a 20 and 30 percent chance of victory, while several others among the “field” are not at all eliminated either. Aronian, Giri, and Anand each have better than a five percent chance. For those geeky readers out there who may have rolled a few 20 sided dice in their time, that’s better than the odds of rolling a natural 20! We all know it can happen!

Here is our updated graph of each player’s round by round odds through the first two events:

GCTpostSinq

Certainly London will be a show worth watching. Halfway through the Sinquefield Cup it appeared that Topalov might be completely running away with the Grand Chess Tour, making London just a battle for second place, but conveniently for those of us who, as fans, might prefer some drama he fell off the pace in the second half and now the field is wide open again!

As for the Sinquefield Cup itself, there’s not so much to say, as we got exactly what we expected. After leaping to a commanding lead in round 7, Levon Aronian coasted to a comfortable victory by drawing his last two games – which was all he needed to win the event outright. The odds of victory are quite straightforward once an event is over: Aronian sits at 100%, all the others tied at 0%. Not much to see there. We can stick it on a graph, though, and see how each player progressed through the 9 rounds, and how people’s chances ebbed and flowed before Aronian eventually locked down first place:

SinqFinal

And thus concludes an exciting Sinquefield Cup. There were certainly plenty of plot twists. Three different players took turns as the favorite, and it wasn’t until round 7 that anyone emerged with much over a 50% edge against the field, so it took a while to find a winner. Furthermore the results drew the Grand Chess Tour standings more tightly together, and increased the prospective intrigue of the third and final leg. All together, it’s hard to have asked for much more from a tournament! Unless you were rooting for someone other than Aronian, I suppose…

So what will happen in London? Well of course we can’t say what WILL happen, that’s why we couch everything in probabilities, but we can at least give an early preview of each player’s odds of winning that final leg:

Player Live Rating London Odds
Magnus Carlsen 2850.1 27.3%
Hikaru Nakamura 2816.2 13.9%
Veselin Topalov 2813.1 13.0%
Viswanathan Anand 2803.1 10.4%
Anish Giri 2798.1 9.3%
Fabiano Caruana 2796.1 8.8%
Levon Aronian 2784.1 6.6%
Alexander Grischuk 2774.1 5.1%
Maxime Vachier-Lagrave 2758.0 3.3%
Michael Adams 2741.8 2.2%
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