D05: Queen's pawn game, Zukertort variation

D05 Sub-variants:

• Queen's pawn game
  1. d4 d5 2. Nf3 Nf6 3. e3 e6
• Queen's pawn game, Zukertort variation
  1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Nbd2 c5 5. b3
• Queen's pawn game
  1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Bd3
• Queen's pawn game, Rubinstein (Colle-Zukertort) variation
  1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Bd3 c5 5. b3
• Colle system
  1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Bd3 c5 5. c3