Skip to main content
ABC News
How The Longest Game In World Chess Championship History Was Won

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

Ian Nepomniachtchi took off his blazer on the third move, a record-fast time, and he played with a captured chess piece like it was a fidget spinner. Across the table from him in a glass box in Dubai sat Magnus Carlsen, the world No. 1. The two, locked in the middle of a weeks-long battle for the World Chess Championship, would be sitting there for a while. More than eight hours later, at the postgame press conference with his jacket back on, Nepomniachtchi would wonder what had gone wrong.

Within a few moves, Carlsen offered to sacrifice a pawn on the altar of attack, a gambit he had tried twice before in the match, which had yet to see a win. It was a creative idea, celebrated by the commentating experts, in this version of the Catalan opening, territory they had also visited last weekend in Game 2.

Nepomniachtchi declined the pawn and offered his own piece of aggression. Chess analysts offer a variety of punctuation for notable moves. Nepomniachtchi’s 11th move was universally awarded an exclamation point — with “11 … b5!” he successfully navigated the opening with the black pieces and bared his teeth, showing his own willingness to do battle. A few moves later, Nepomniachtchi declined to trade queens, again demonstrating his tenacity. Two entrenched, well-equipped armies stared at each other across an empty no-man’s land in the middle of the board — the silence before the fury and long war of attrition to come.

Nepomniachtchi soon offered a trade of his own — one white queen for two blacks rooks. Carlsen accepted these terms, and the imbalanced position teetered precariously on the board. The players’ clocks ticked while they contemplated how it might all crash down.

Players begin world championship games with a bank of two hours — they gain a bonus hour only once they make their 40th move. If a player’s clock reaches 0:00, they lose. By the 30th move, Carlsen’s clock had drifted below 10 minutes. By the 35th, both his and Nepomniachtchi’s clocks were under five minutes.

For so much of the match, the computer evaluation had sat level near 0.00, representative of the dead-equal and nearly perfect chess played by both grandmasters. During this feverous stretch of time trouble that followed here, however, the computer twitched like a seismograph during the Big One.

Clocks draining, Carlsen and Nepomniachtchi were locked in an intricate battle for space and material in the board’s southwest corner — an asymmetric skirmish, queen and bishop versus rooks and knight. Carlsen was the first to see real winning chances, but he missed a chance to spring a fruitful long-distance attack on the black king. (Carlsen said after the game that this idea hadn’t been on his radar.) Shortly thereafter, Nepomniachtchi ought to have grabbed a free pawn but did not.

They each made their 40th moves with mere seconds to spare, the computer once again displayed 0.00, and the clocks wound to an hour apiece. 

But four hours into play, there was still a rich, fraught endgame to come. With his king safely tucked away and some time on his clock, Carlsen was free to investigate his attacking chances once again.

A painstaking dance unfolded over dozens of moves, as a few pawns were gobbled up and pieces rerouted to just the right places. On the 80th move, Carlsen traded one of his rooks for a pawn and bishop, and the survivors were as follows: a rook, a knight and three pawns for Carlsen; a queen and one pawn for Nepomniachtchi.

It was some 30 moves before another pawn was moved, and no pieces were captured, as the bigger guns bobbed and weaved, darting in and out of traffic, and with similar consequences should they not look both ways. By the 100th move, Nepomniachtchi’s chair was shaking visibly, another seismic event. As moves crept further into triple digits, Carlsen started checking his scoresheet, wanting to avoid the threefold repetitions of position that would be declared a draw, and instead pursue victory, however long it took.

By the 116th move, the game could be found in endgame tablebases, those precalculated positions made known by modern machines — the game was a theoretically guaranteed draw. That doesn’t mean the draw is easy for a human to achieve. Nepo had to navigate a minefield while taking on heavy fire, finding just the right moves to hold the draw, while Carlsen was playing essentially without risk.

On the 125th move, it became the longest game in world championship history. 

On the 130th move, Nepomniachtchi put a foot wrong. A powerful computer analyzing the match found a guaranteed checkmate 60 moves into the future.

Chart showing a line chart of Game 6 of the 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. After Ian Nepomniachtchi missed a free pawn in move 36, Magnus Carlsen held the advantage for the rest of the game. Game 6 ended with a historic win from Carlsen.

It wouldn’t take quite that long. Nepomniachtchi offered his hand in resignation after 136 moves over nearly eight hours, as Carlsen’s pawns were unstoppable, bound for promotion at the far end of the board. Carlsen now has the lead in the best-of-14-game match, 3.5-2.5, and the contest could stretch until mid-December.

In a match defined by flawless play, a few human mistakes on Friday introduced deep drama and turned the game into an instant classic. Nepomniachtchi described the play of both players as “far from excellent,” but the game itself was superb. 

“I was running on fumes at the end,” Carlsen said at the postgame press conference, chalking the game up as win like any other, with familiar nonchalance.

And how does Nepomniachtchi bounce back? “Hopefully in style,” he said.

The match continues through the weekend, with Game 7 on Saturday and Game 8 on Sunday — both begin at 7:30 a.m. Eastern. We’ll be covering it here and on Twitter, keeping a close eye on our clock.

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.

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.