George Jempty wrote on 05/02/12 at 19:51:02:
I know I started this mess but I will add this. I played a Gruenfeld as Black against someone rated 500 points higher than me last week on ICC. He automatically played the Exchange variation, but then took 25 seconds to play 7. Bc4 -- enough time to load it up in chessbase, and a move you should either play automatically, or not (because you play Nf3 and Rb1). After my out-of-style 10...Qc7 he takes a minute to find the book response 11. Rc1 -- also perhaps enough time to familiarize himself with a bit of the tree depending on how things progress. And then after my 11...Rd8 he rattles off three book moves in a row with no thought leading him into a position that is 70+% for White.
Earlier today I showed the game to my coach, an IM, and without any prompting on my part, *he* commented on the possibility that my opponent was using a book or database.
In addition to the reasons already mentioned, I can see another plausible explanation for taking time for 7.Bc4: If your opponent has just started playing this line, he may have been uncertain about the move order. The first six moves are easy to remember, but on the seventh, White has many natural moves, and even if your opponent remembered he was going to play Bc4 at some point, he may have wondered if he was supposed to play e.g. 7.Be3 first.
Then, when he took a minute playing 11.Rc1, I can see at least two plausible reasons that don't involve cheating or distractions:
1) Your opponent vaguely remembers learning about 10...Qc7, but of course, he has focused mainly on 10...Bg4. Now his thoughts go something like this: "Against 10...Qc7, the right answer is 11.Rc1, isn't it? But wait a minute - what was I going to do after 11...Rd8? There was some tactical stuff here, and 11.Rc1 really doesn't make sense if I don't have a good reply to 11...Rd8. Oh, I think I remember now, this is the line I studied..." And when he is confident he remembers the right answer to 11...Rd8, he plays 11.Rc1, and then plays the next moves immediately.
2) Your opponent has hardly studied 7.Bc4 at all, and is actually out of book when you didn't play 10...Bg4. However, he is a strong player, digs as deeply into the position as he can given his short time, and then plays 11.Rc1. He may not be 100 % confident he has found a good reply to 11...Rd8, but he has calculated a line which looks good for White. You make the replies he has expected, and since he has already spent a considerable amount of time, he uses the opportunity to play some quick moves that he has already planned in advance.
In fact, reason 1) is exactly what happened to me the first time I played the 7.Bc4 line - except it was a serious OTB game, so I took probably 10-15 minutes before playing 11.Rc1, and maybe a minute or two on each of the next moves.