Develop both bishops: Queen's Gambit line

Repeat the setup. Support your central pawn and develop your other bishop while Black castles.

1. d4
2. d5
3. c4
4. e6
5. Nc3
6. Nf6
7. cxd5
8. exd5
9. Bg5
10. Be7
11. e3
12. O-O
13. Bd3