Chess Opening Theory/1. d4/1...d5/2. c4/2...c6/3. Nc3/3...Nf6/4. Nf3/4...e6/5. e3/5...Nbd7/6. Bd3/6...dxc4/7. Bxc4/7...b5/8. Bd3/8...a6/9. e4

Meran variation D47-D49 Semi-Slav 9. e4 White strikes in the center, opening up the dark-squared bishop in the process. Black's main move is /9...c5/, looking to break up White's center immediately. This move is played in the vast majority of games, and is Black's best option to open up the light-squared bishop and fight for an advantage. A very rare sideline is /9...b4/, the Pirc variation. This is the only other move (according to chess engines) that doesn't give White a winning advantage, since it gains a tempo on White's knight. Theory table Old variation 9...c5 10. e5 cxd4 Reynold's variation 9. ... ... 10. d5 c4 Pirc variation 9...b4 10. Na4 c5 References Semi-Slav Defence Meran Variation: 6.Bd3