Calculating Two Moves Ahead

Snuffington: The point is that no major blunders were made and Fischer was able to get in a favorable position. And, no, blunders are not arbitrarily named by the computer or people--they are moves that significantly shift the game in one player's favor.

In top rated games, when a blunder occurs, there is more often than not a resignation shortly to follow.

In the game I described, this did not happen. Yes, there were more subtle "mistakes" made, and there would have to be to warrant calling it an "overwhelming advantage," but nowhere near anything this case study shows. Nor was it a single move that had Spassky at a loss. It was the result of brilliant strategic play.

In game 2, Fischer (and Spassky) played even better, without even a single inaccuracy. Still, Fischer lost with white. (Which proves that chess is a forced win for black.)

@mattrenter

"The point is that no major blunders were made and Fischer was able to get in a favorable position."

Well, apart from the difference between "a favorable position" and "overwhelming advantage," you've also changed "mistake" to "major blunder." So now it's a different statement. But nevertheless, the point is true: Unless you believe one side starts with an advantage, then it must be that mistakes (or at least one mistake) were made if somebody has a significant advantage.

"And, no, blunders are not arbitrarily named by the computer or people--they are moves that significantly shift the game in one player's favor."

Yes, they are arbitrary. What constitutes significant? That's an arbitrary judgment, one made by whomever programs whatever individual software.

If somebody has a significant advantage, and a computer says no mistakes were made, then it can only be because either one side starts with an advantage, or that the computer is not advanced enough to identify the mistake. It cannot, however, be that the sides start even, and yet one side gains a significant advantage without a mistake being made.

@Dr_King_Schultz

"Which proves that chess is a forced win for black"

Or it proves that computer software isn't able to identify the inaccuracy.

It is not true that the 6th match game Fischer - Spassky 1972 contains no mistakes.

14...a6? was a mistake and Spassky should have played 14...Qb7.
18...Qf8? is an error and Spassky should have played either 18...Nf8 or 18...Nf6.

@Snuffington

I never changed my statement. I meant "major mistakes" to mean blunders the whole time, and yet you're continuing to split hairs and zero in on single phrases while completely missing the point.

You overlooked the fact that I agreed with you. Yes, some degree of mistakes have to be made to get in a an unfavorable position. I never said any side starts with an advantage, so stop pushing an argument I never made.

The point is real simple: at top level play, it comes down to more subtle inaccuracies. Not blunders.

Keyword inaccuracies. They're not perfect play. They're just less obvious/game changing than full blown blunders.

@Snuffington

What exactly is the argument you're making? Are you saying there is no distinction between a blunder and an inaccuracy? Because I think there is.

In a mathematical sense a blunder is a move that turns a won position into a lost one and an error is a move that turns a won position into a drawn one or a drawn position into a lost one.

I always thaught of a blunder as drastically changing the evaluation. It depends on the position what you could call a blunder and an inaccuracy.
In some cases a shift of 1 could be considered even a blunder. Where as in other cases possibly a shift from the best move of 1 would be only an inaccuracy.

Say you had 3 completely winning moves
One was +13
One was +12
And the last one was +11.8

Well to call the move a blunder if you picked option 3 is ridiculous.

But if you have 3 moves:
Option 1: +.7
Option 2: 0
Option 3: -1.5

I guess you could call picking option 3 a blunder because likely at 1.5 you are now lost. You turned a .7 advantage into a 1.5 disadvantage.

Prospective people. Prospective. It depends on the position and your own value of a blunder. To me its going to be different I would assume to someone else.

In some cases lichess analysis says giving a pawn for zero comp is a mistake where as in my view its a blunder if you just hang a pawn. I play objectively.