All it took was one impulsive move from Viswanathan Anand to ruin the results of hours of cool-headed defence.

The World champion’s oversight on the 45th move in a materially-equal position against challenger Magnus Carlsen turned the fifth game of their World chess title-match on its head.

Eventually, Carlsen drove home the advantage of playing with white pieces, in 58 moves. The score in the 12-game match stands at 3-2 in Carlsen’s favour.

In the sixth game on Saturday, Anand plays white.

Recipe for success

For Carlsen, this has precisely been his recipe for success in the past few years: take an equal battle into the fifth or sixth hour of play, and believe the rival would play at least one sub-optimal move owing to tiredness or lack of resilience.

On Friday, too, his belief paid off.

Anand failed to objectively read the position, much before he actually faltered. This was quite evident from the fact that both players pointed to black’s vigorous rook-manoeuvre on the 34th move, but analysed it differently.

“I was worried I missed something. I thought I might even be worse. Probably I was not,” said Carlsen, looking back at Anand’s rook-move. The latter, understandably distraught, was more categorical. “There have been small inaccuracies, but Rd4 (black’s 34th move) turned out to be a mistake.”

In fact, Houdini 3 Pro, a search engine used by most leading players across the globe to prepare, suggested that the move Anand played on the 34th turn was the best option that negated whatever little positional advantage Carlsen had enjoyed at that stage.

In fact, Houdini pointed to Anand’s 45th move — which saw the champion give a rook-check to the challenger’s king from the back-rank on the queenside — as the game-changer.

New opening

As expected, Carlsen chose to test Anand with a new opening after the Reti Opening proved ineffective in Games One and Three. In this variation of Semi-Slav, Anand’s first notable triumph, from the black side, came against Vladimir Kramnik in 1997.

Within minutes of the start, Carlsen showed how confident he was. On the sixth move, he chose to stay away from battling sharp lines and got the ‘dry’ position he loves. “Relatively interesting opening,” said Carlsen and continued, “I got some advantage. The position I got today was nice. I had better bishop and better pawn structure. I could consolidate and put a bit of pressure.” Carlsen then opted to get rid of the queens on the 15th move, setting the stage for a long battle.

It was clear that the Norwegian was in his comfort zone and ready to test Anand’s preparedness. Until Carlsen’s 32nd move, Anand looked to be defending rather passively, but effectively.

Off the next two moves, Anand’s rook-manoeuvre to the middle of the board showed his intention to take the bull by the horns.

Losing battle

However, contrary to the belief of millions who followed the game with computer-assisted guidance, Anand thought he was already fighting a losing battle.

Carlsen said, “At this point, I did not think too much in terms of winning chances. It turned out to be more difficult than I thought. It was a good fighting game. I got there in the end so I am very, very happy.”

Anand, looking back at the game, said: “Somehow I missed (something in) the rook-ending… it’s so difficult. I thought I would be able to generate counter-play but it wasn’t possible. Today, he took his chances well.”

Before leaving, Carlsen said, “It is not the one who wins first that wins the match. It’s a good start. Now he will have two whites (in the next two games) and he’ll have his chances to make his move as well.”

The result: Game Five: Magnus Carlsen (Norway, 3) bt Viswanathan Anand (India, 2).