5 Puzzles: QGA, Classical 6...a6
This is another huge favorite of both Anand and Kramnik (See my recent blog post on the Sveshnikov/Pelikan). Anand has played this 32 times as Black and Kramnik has led with it 34 times as White. It could very well be the critical game of the Championship is a D27 QGA. To review, the games begin, 1.d4 d5 2.c4 dxc4 3.Nf3 Nf6 4.e3 e6 5.Bxc4 c5 6.O-O a6. Here are a few crucial positions from miniatures. None of these games lasted 20 moves.
More D27 QGA puzzles can be found at wtharvey.com/d27.html