12...O-O is probably black's best reply to 12.Re1 and, after this, white's best is probably 13.Ba3 a simple transposition (or 13.Rb1). If 13.exf6 the proper response is not 13...gxf6 but instead 13...Rxf6 (14.Ba3 Nf5) and the game is very nearly equal.

In any event, 12...Ng6 should be regarded as a mistake, after 13.Ba3 and the ensuing exchanges white has a clear advantage. Larsen simply neglect to castle either short on move 12 (best) or long on move 17.

Second, 17...Kf7 was not an interesting move "with verve and imagination" it was not even dubious it was a mistake that solidified white's advantage. Here, castling long and inviting 18.Qxa7 or moving a6 and inviting 18.Qxd5 were black's two best perhaps only viable options.

After 18.f4 the only strong move, black plays best replies but by 20...Kf6 Larsen is losing. As <PSC> points out Fischer missed the winning move 21.Bd6! After 21...Qd8 (or 21...Qc8) 22.Bf3 Be6 (or 22...Bc6) 23.Qd4+ and black can resign.

After Fischer's mistake 21.Bf3 the game is equal again. With 22...Kg6 white has several good options (Rxe5 or Be2 or Kh1 or others like Bd6 or Bxb7) all with about equal chances, the game is quite complex. Fischer's decision Rxe5 resulted in material gain but giving Larsen the initiative. As such, 25...Qe3+ played was probably best.

Both players are very accurate (including 32...Qxc3 it was best) and, despite the material imbalance, after 34.Bxa7 the games is equal with several choices for black. Although equal, the pressure builds on Larsen who starts getting inaccurate, as Houdini shows (lines truncated):

click for larger view

27/73 50:57 16,050,164,704
0.00 34...Ke6 35.a5 Qxa5 36.Bd4 Qd2
-0.03 34...Ke5 35.Bc5 g5 36.Rd1 Qxc2
-0.06 34...g6 35.a5 Qxa5 36.Bd4+ Ke7
-0.15 34...f4 35.a5 Qxa5 36.Bd4+ Ke6
-0.30 34...Ke7 35.Bc5+ Ke6 36.Rd1 Qxc2
-0.35 34...Kf7 35.Bb6 Qxc2 36.a5 Qd3

34...g5 and 36...Qb2 (instead of 36...Qa2) another small inaccuracy gave Fischer a small edge. But then 38...Qa3 (instead of 38...Qf2) was a very subtle mistake that should have been decisive. Here, Fischer again did not choose the winning move 39.Re1+ but this time 39.Bb7, second best, at least kept up the strong pressure. Larsen finally collapsed with 39...Qc5 (instead of Qb3) that loses on the spot.

Tal expressed that sentiment:

<I shall observe for the thousand and first time: years of analysis and minutes of play are not quite the same thing.>

Janowski was the one legendary for excuses, but one of my favorites was Tarrasch's excuse for losing the 1908 match (disturbed by sea air). Since it was played 100 miles or so inland, even a magazine that had supported him editorialized that maybe a chessplaying gift that delicate wasn't robust enough to be world champion. (You've got to love the days when people knew how to be insulting wittily).

That's long been one of my favourites as well.

<There's that story (probably apocryphal) about an organizer who offered Janowski some kind of perfect playing conditions. He complained "You've taken away my excuse", and did badly.>

This reminds me of a supervisor in my last job who wasn't happy without a reason to find fault with others.

One night, she came to three of us working together, ticked off several things we might or might not have done to her satisfaction, and on discovering that everything was in order, blew her stack because there was NO reason to complain!

It's not unreasonable to theorize about such things (if Botvinnik's wife hadn't died in 1960, maybe he'd have beat Tal the first time). It's only unreasonable when we start to use it to throw out results. To say that that result doesn't really count because of (such and such). Chess isn't played in a bubble. Real life may play a role, and the winners have to overcome those factors as much as overcome their opponent.

The Fischer-Petrosian match is a good example of this one, because it's one of the rare ones where BOTH sides have excuses.

The Fischer fans make excuses for the fact that Fischer did poorly in the first half. He only broke even, and could easily have lost the first 3. Well, that's just because he wasn't feeling well, they say.

The Petrosian supporters have their excuse for the last half of the match, and it's similar to Larsen's. Petrosian never wanted to play in Argentina, he didn't like the heat, and when the heat and went way up, his results went down.

To give him his due, this was a big issue before the match. Fischer and Petrosian had a long phone call with Gligoric as interpreter over the venue. Petrosian wanted to accept Greece's bid, Fischer wanted argentina because it had a higher purse, and he liked the steaks there (seriously). In the end, the issue had to be settled, Petrosian had to play somewhere he didn't want to, but that's a part of chess and a part of life. The results were what they were, and they counted. If you want to argue that he'd have had a chance in a rematch under better conditions, fine, but this match counted.