Chess is an unforgiving sport.

Only in chess (and boxing) can a player perform well throughout a contest, only to lose immediately through a moment of inattention, a single unforced error. And any loss is entirely your own fault — there is no teammate, line judge or umpire to share the blame.

However some mistakes are worse than others and on Monday night during his World Championship match in Bonn, Vladimir Kramnik suffered the worst kind — an error so basic that the Russian would begin to doubt his own brain’s competence.

Game 5 of Kramnik’s title match against Viswanathan Anand had been proceeding smoothly for three and a half hours when Kramnik, in a roughly equal position, played the most horrible move he had made in a decade, maybe longer. Kramnik could not use time trouble as an excuse — he still had 18 minutes left on the clock when he erred. Nor is age an explanation — senility does not normally set in at 33.

When Kramnik grabbed the fatal pawn, there was a mad dash by journalists from the press centre to the playing hall. Some were ghoulish, though many expected that there had been a transmission error on the live demonstration board and wanted to check out what had “really” happened.

Kramnik had no idea about the commotion — a thin black gauze curtain prevents the players from seeing the audience, an anti-signalling precaution — but soon enough Anand played the winning idea, missed by Kramnik. A minute or two later, Kramnik extended his hand in resignation.

At the post-game press conference, a subdued Kramnik was at a loss to explain his brain explosion, though he did point out that it was a continuing blind spot and only luck had prevented him from falling over the same cliff a couple of moves earlier.

Anand now leads 3.5-1.5 in the 12 game contest, but the Indian’s advantage is far greater than just two wins to nil. Bobby Fischer used to say that he liked to crush the other guy’s ego. Anand now does not have to bother — Kramnik has destroyed his own ego. For the remainder of the match Kramnik will be unable to trust himself, checking and double-checking every move he chooses in case it is another giant blunder.

Kramnik tried to make light of his predicament after the game: “It could have been better,” was his response when asked if the situation was critical. “But it is not totally hopeless and I am going to fight.”

Kramnik is renowned for his recovery skills, having fought back from a game down in his two previous world title matches. However he has never been so far down so early in a title fight and Anand’s knock-out blow could come as early as Tuesday night.

Bonn 2008

Game 5

White: V.Kramnik
Black: V.Anand

Opening: Queen’s Gambit Declined

1.d4 d5
2.c4 c6
3.Nf3 Nf6
4.Nc3 e6
5.e3 Nbd7
6.Bd3 dxc4
7.Bxc4 b5
8.Bd3 a6
9.e4 c5
10.e5 cxd4
11.Nxb5

With his seconds having worked through the last three nights to find a hole in Anand’s favourite system, Kramnik is willing to repeat the super-sharp opening which featured in game 3.

11…axb5
12.exf6 gxf6
13.0-0 Qb6
14.Qe2 Bb7
15.Bxb5 Rg8!?

Unfortunately for Kramnik, Anand gets his retaliation in first, avoiding 15…Bd6.

“Compared to game 3, this gives White the option to play Bf4-g3, so I did it.” Kramnik said.

16.Bf4 Bd6
17.Bg3 f5
18.Rfc1!

Kramnik was not impressed by Anand’s “tricky” plan and was very pleased with the “delicate” response he found, albeit with his clock already showing less than an hour remaining: “I couldn’t find a clear way, though it looks very dubious for Black.”

18…f4
19.Bh4 Be7!

“I think this is a good plan,” explained Anand.

“Of course it is very risky to put the Black king on e7 but I didn’t see how White could attack without his dark squared bishop.”

20.a4! Bxh4
21.Nxh4 Ke7
22.Ra3 Rac8

Anand also considered 22…Rg5 — “It’s an incredibly unclear position; probably both moves are fine [for me],” he explained. “But I wanted to take over the c file.”

23.Rxc8

“23.Rd1 was very interesting but I was running short of time and decided to simplify,” explained Kramnik. “With more time I would probably play 23.Rd1.”

23…Rxc8
24.Ra1 Qe5
26.Nf3 Qf6!
27.Re1

Kramnik traced his downfall to this move, on which he took six minutes without seeing the trick which cost him the game. 27.Bxd7 Kxd7 28.b4 was safe and sensible for White.

27…Rc5
28.b4 Rc3

Kramnik thought that this was unplayable, expecting

28…Ne5
29.Nxe5 Rxe5
30.Rxe5 Qxe5
31.Qh4+ Kf8
32.Qd8+ Kg7
33.Bf1

“when I can at least try for something with my pawns on the queenside.”

Anand explained that he thought for a while about 28…h5 but decided to give Kramnik a chance to go wrong, hardly believing that his illustrious opponent would take the bait.

29.Nxd4??

“If I don’t play this, Black is already fine,” said Kramnik, rationalising why he played this disastrous, move without much thought. Alarm bells should have been ringing but Kramnik was deaf to them.

29…Qxd4
30.Rd1 Nf6!
31.Rxd4 Nxg4
32.Rd7+ Kf6
33.Rxb7 Rc1+
34.Bf1 Ne3!!

“I had seen this resource a long time ago,” said Anand — as far back as move 26.

35.fxe3 fxe3 0-1

Watch the game here: