There is a mainframe computer called “Sesse” in Trondheim, Norway, on which the open source program “Stockfish” performs particularly in-depth analyzes during World Cup games.

When there are only a few pieces left on the board, “Sesse” often reckons with thirty white and thirty black moves in the future.

Or even further.

Very often, "Sesse" shows a rating of 0.00.

This means that when arithmetic, positions are reached in which there is no more in sight or which are already stored in a database as a draw. 

When Magnus Carlsen only has three minutes left for eight moves during the sixth game, “Sesse's” rating begins to go crazy. It jumps from 0.00 to 3.66. Winning position for white. Jan Nepomnjaschtschi has apparently made a mess. On move 36, Sesse reads -2.07. Big advantage for black. Carlsen missed his chance! On the 39th move, the rating is 3.08. Again winning position for White. Soon it will be 0.00 again. 

Of course, the world champion and his challenger do not see these ratings.

But almost everyone who follows their games on the Internet.

Most broadcasts have computer ratings built in.

You don't even have to understand a lot about chess to know who made a mistake and when.

But the computer evaluation does not explain who has a chance of winning and why.

That's what human commentators do, and they agreed for most of the sixth game that Carlsen was on the trigger. 

"Jan will kick his ass"

After the defending champion had to defend himself for the whole game in a Spanish opening with Black on Wednesday, he now had White and, like in the second game, is betting on the Catalan opening. On the tenth move he offered a prepared pawn sacrifice, but Nepomnyashchi refused to accept it. Later he offered the world champion the opportunity to swap his queen for both black rooks. Carlsen was delighted: "It's risky for both of them, but it was riskier for him." 

Some of Nepomnyashchi's later decisions also surprised the commentators.

"Jan will kick his ass," said 2018 defeated challenger Fabiano Caruana on Chess.com.

Instead of trying to play the best moves, the Russian was looking for confusion.

In his own time constraint, Carlsen missed opportunities to take a clear advantage before move 40.

After that, a draw was the most likely result until shortly before the end. 

After seven and three quarters of an hour and 136 moves, Nepomnyashchi surrendered.

"It wasn't an excellent game on either side," said the Russian.

Carlsen, who is now leading 3.5: 2.5, had to wait five years and nine days to win a World Cup game with a long cooling-off period.

136 moves make it the game with the most moves in the history of the World Chess Championships.

The longest World Cup game to date was played in Baguio City in 1978: Viktor Korchnoi tried 124 moves to beat Anatoly Karpov before he went into a draw.

At that time there were still hanging games and the game was interrupted and adjourned twice.

And every matchday was followed by a day off.

In Dubai, on the other hand, the seventh game and Nepomnjaschtschi behind the white stones continue on Saturday.