411 REFERENCE · Wikibooks
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. e4/9...c5
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Meran variation D48-D49 Semi-Slav
9...c5
Black strikes back at White's center, opening up the light-squared bishop.
This is the main branching point of the mainline Meran, since White has to choose between one of two pawn breaks: e5 and d5.
/10. e5/ is the Old variation.
/10. d5/ is Reynold's variation.
Theory table
Old variation 10. e5 cxd4 11. Nxb5 axb5 12. exf6 gxf6 Reynold's variation 10. d5 c4 11. dxe6 fxe6 12. Bc2 Qc7
References
Semi-Slav Defence Meran Variation: 6.Bd3