Valencian Variation, Main Line

The Main Line of the Valencian Variation arises after 4. d4 Nf6 5. Nf3 Bg4. Black brings the queen's bishop out before ...e6 can shut it in. The bishop pins the f3-knight, which is the main defender of d4, so White has to reckon with pressure on that pawn. Black's usual follow-up is ...c6 and ...e6, a compact structure with few weaknesses. White's main decision is whether to tolerate the pin or challenge the bishop at once.

The most frequent reply is 6. Be2, a quiet developing move that breaks the pin and gives results close to even in online play. 6. h3 is less common, but it scores better for White and is the engine's first choice. After 6. h3 Bxf3 7. Qxf3 c6 Black has conceded the bishop pair in return for a solid position. The greedy 7...Qxd4 loses to 8. Qxb7, which wins the rook on a8. 6. Bc4 develops the bishop to an active diagonal and scores about evenly. Engines also rate 6. Bf4 highly, and they assess the position as a slight edge for White.