What does Kasparov mean by "I was behind in three and even in one after six games"? This not a question about chess exactly but I'm reading Deep Thought by Kasparov and I didn't understand what he meant by "I was behind in three and even in one after six games" when he was describing his matches with Karpov.


  In my five world championship matches against Karpov, I was ahead after six games in only one, our last match in 1990. In the other four I was behind in three and even in one after six games, but didn’t lose any of them in the end, winning two and drawing one. (Our first match was terminated after I came back from 0–5 to 3–5.)


Does this mean that he was three games behind in the first six in one match and one game behind in the other?
He is talking about the score after the sixth game of each of his matches with Karpov. To be precise, these were the scores after game six (shown as Kasparov-Karpov, not counting draws, to follow the same convention as the quote from the book):

1984: 0-2
1985: 1-2
1986: 1-1
1987: 1-2
1990: 1-0


As you can see, Kasparov was behind after the sixth game in three matches: 1984, 1985, and 1987. The score was even in one: 1986. Put both facts together and you have "behind in three and even in one". And indeed in only one match, 1990, Kasparov was ahead after the sixth game.