Orthodox Defense, Main Line

The Main Line of the Orthodox Defense arises after 7. Rc1. The rook move is useful in almost any version of the position. It places the rook on the c-file, where it will matter once the c-pawns are exchanged, and it keeps White's options flexible while Bd3 is held back. Black now usually decides how to resolve the tension at c4. The most common reply is 7...c6, which normally leads after 8. Bd3 dxc4 9. Bxc4 to the classical positions in which Black is cramped but has gained a tempo, and frees the game with Capablanca's exchanging plan or with ...b5 and ...Bb7.

Black has other options. The move 7...b6 prepares a queenside fianchetto without committing the c-pawn. The Henneberger Variation, 7...a6, prepares ...dxc4 followed by ...b5 with gain of time. The engine also favors 7...h6 and the immediate 7...dxc4, and it rates the position as roughly balanced. The line is played far less often than 7. Bd3 in online games, and results from it are close to even, with very few draws.