One of the fascinating aspects of World Championship Opening Preparation is that, like any good controversy, there are two sides to each story. In 'Did You Consider Just Playing Chess?', we heard Kasparov's opinion on his 2000 title match with Kramnik, as recorded by Dirk Jan ten Geuzendam in 'The Day Kasparov Quit'. Here is Kramnik's opinion according to the same source (p.208):
Q: Kasparov said that his opening repertoire proved useless when he ran into an opening repertoire that you had been forging for three years, to be untouchable as Black.
A: No, I can tell you honestly, on this endgame [the 'Berlin Wall'] I'd been working for two weeks. It was in no way the only weapon I had, but it was good enough. In fact it was mostly psychological, because it is clear that White is slightly better in this endgame. But I knew that he wouldn't like it for several reasons. First of all, computer preparation is useless here. Also it is not his type of position. The other thing which is quite important actually is that the Petroff Defense, which I have been defending a lot with Black over the past few years, helped me a lot in this match. I always ended up with worse positions and in the end I was no longer afraid of them. [...]
Q: Were you surprised he kept returning to this Berlin Defense?
A: Not really. Because, whatever he may say, he understands that White is pressing in this endgame. It was also a challenge for him. He immediately gets this slightly better endgame; I don't even fight for equality. He fails once or twice and then he wants to prove he can win it. That was a mistake, probably. [...]
Q: In recent games you were playing very aggressively. Did you want him to get the idea that you might play like this?
A: Yes, of course. Also this 1.e4 gainst Leko in Cologne [a few months before the Kasparov match] was to create the idea that I was preparing for 1.e4 and an aggressive approach. [...]
Q: Does this result confirm a favorite statement amongst top players? Take away Kasparov's openings and he is still a strong player, but nothing more than that?
A: I don't want to insult him, but in a way this is true. He's a brilliant player, an absolutely brilliant player with his openings and still an excellent player without his openings, but already not better than some others. In any case he is not better than me. Actually now I am sure that I am stronger than him in pure chess, which I proved. It isn't true that I was much better prepared. You simply look at the games. I was psychologically better prepared. My preparation was cleverer. I was getting him in positions that he doesn't like. [...]
Q: Some of the ideas came from people outside your direct team. Kasparov was shocked when he heard about the extent of this help and learned that also people like Gelfand, Morozevich, and Svidler helped you.
A: I don't see any reason for him to be surprised. Just pay and they work for you. I spent a lot of money on preparation. He could also have hired five 2670 players but he didn't. It's his own fault.
Kasparov said, 'It's clearly not as much Kramnik's win as my loss', a sentiment with which Kramnik, just as clearly, disagreed.