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Brilliance And Blunders Have Defined The World Chess Championship

This article is part of our 2021 World Chess Championship series.

Magnus Carlsen of Norway continued his unrelenting march toward the world chess title on Wednesday, holding his challenger, Ian Nepomniachtchi of Russia, to a quiet draw over 41 moves in just over two hours. With a 6.5-3.5 score in the race to 7.5, Carlsen is all but guaranteed to extend an unbroken reign atop the game that began in 2013.

Carlsen played field marshal to the white pieces on Wednesday, but there wasn’t much of a battle. After yet another beginning in the Petrov opening, both sides safely and quickly steered the game toward peaceful pastures.

“There are so few games to go that any draw is an excellent result,” Carlsen said afterward.

Chart showing a line chart of Game 10 of the 2021 World Chess Championship and a small multiple grid of line charts for all the games so far. Each line chart shows the advantage by player after each move. This was largely an uneventful game, with Magnus Carlsen holding a slightly advantageous position for most of the game. The overall record is now three wins for Carlsen and seven draws.

The game was a respite from the disasters that shook the previous two games, in which Nepomniachtchi blundered a pawn and then a bishop, respectively, losing both and ceding any realistic hope of becoming world champion. (As someone who once blundered about six times versus Carlsen in a single game, I empathize.)

“I tried to play a normal game and not to blunder something in one move,” Nepomniachtchi said Wednesday, only half-joking.

After 10 games, this has been a tale of two matches, featuring both the impressively precise and the inexplicably misguided. By one measure, this year has seen the three most accurate games in World Chess Championship history; it has also seen the 408th, 446th and 723rd most accurate games.

To quantify this, we looked at data from every championship ever played, assembled by Lichess — a set of 1,034 games dating back to 1886. The accuracy of human chess play is often judged by superhuman computers using the metric of “average centipawn loss” — that is, by how many hundredths of a pawn a player deviated from the most accurate move calculated by the machine.

Perfection and blunders at the chess championship

Average centipawn loss, historical rank of each game’s accuracy and the inaccuracies, mistakes and blunders for Magnus Carlsen and Ian Nepomniachtchi, by game in the 2021 World Chess Championship

Average centipawn loss Carlsen Nepo
Game Carlsen Nepo Combined Rank I M B I M B
1 8 7 15 103 1 2
2 9 10 19 196 3 3
3 2 3 5 2*
4 7 6 13 60 1
5 6 6 12 49 1
6 🏆 12 20 32 446 2 2 6 1 2
7 2 2 4 1
8 🏆 20 32 52 723 2 1 1
9 🏆 10 20 30 408 1
10 3 2 5 2*


Average centipawn loss is the number of hundredths of a pawn by which a player deviated from the most accurate move calculated by a computer.

Source: Lichess

The Lichess analysis, powered by the Stockfish chess engine, also awards a variety of demerits to imperfect play — “inaccuracies,” “mistakes” and “blunders.” Unsurprisingly given the match score, Carlsen holds the edge in all categories. In the instant-classic Game 6, the imperfections were largely driven by time pressure. In Games 8 and 9, the blunders were more mysterious, perhaps driven by the general pressure of the world championship. The best explanation may simply be that chess is hard.

The match rests tomorrow. Game 11 begins Friday at 7:30 a.m. Eastern time, and we’ll be covering it here and on Twitter, trying to avoid any blunders of our own.

Seven Games by Oliver Roeder

For even more writing on chess and other games, check out Roeder’s new book, “Seven Games: A Human History,” available in January.

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Oliver Roeder was a senior writer for FiveThirtyEight. He holds a Ph.D. in economics from the University of Texas at Austin, where he studied game theory and political competition.