 Complete the following phrase:  This variation is also a popular line. Placing the bishop on Bg5 allows Black to exchange more freely with moves like Nf6-e4, as seen in the Lasker Defence. The move Bf4 is designed to restrict Blacks opportunities in this way, as well as reducing opportunities to gain the bishop pair. Play usually continues with 5...0-0 6. e3 c5 7. dxc5 Bxc5. Peter Leko, usually an e4 player, used this variation as White to beat Vladimir Kramnik in their 