Greatest blunder in the history of chess?

 What is greatest blunder of all times??

Bobby Fischer taking up chess in the first place. He should have been a stockbroker where psychopathy is the norm and greed is good and busting the other guy's ego is par for the course.

What criteria make a blunder great?

Probably any missed mate in 1, for or against. Maybe Kramnik v Deep Blue?

Cheparinov not shaking hands with Short. Losing the game without a move. That's a blunder.

Greatest blunder of all time? If you had all of the games I've ever played on record, you'd be able to find the answer.

In chess ?

Here's a blunder by a former WCC

not the greatest of all time, but it still loses the game to a back-rank mate in 3, you'd think Alekhine would spot such threats

That is truly abysmal. What was Alekhine drinking?

A nice blunder was Kramnik's missed mate in 1 on h7 in a match against computer.

Also I remember a grandmaster's blunder on move 7 or 8 when he pushed his pawn in the opening d2 - d4, attacking black's queen on g5 with a bishop on c1. However, black just played Q:c1+ and grandmaster playing with white immediately resigned, cause nothing was protecting the bishop :)

Refering to a game between Stripunsky and Onischuk in the US Championships.

yes, that one =)

yes, the mate might not be forced, but i think that the existence of the mate threat (after Qxd7+) is what really makes the attack devastating and wins the game

Not that that mattered to him particularly...

Whoever fell for the first fool's mate made the worst blunder ever.

Surely it's worse to repeat it?

But if nobody played it first, then it would never be played at all, would it? Good point though...

As a serious answer, Chigorin against Steinitz, in Cuba, allowed mate from a dead even position. 

AndyClifton -  I guess you mean in the US.  Chess was popular in most of the world before Fischer, just not here at home.

Ivanchuk missed a mate in one against Anand, that must have been bad.