Middlegame Structures: Open Position
One of the best ways to study the middlegame is to think of the positions in terms of the pawn structure and how the specific piece placement as well as the changes in pieces and structure shape the games we play. The more aware a player is of the dynamics of a structure (typical plan, transformations, ideal piece placment) the better they will play the game in general.
Here we have the open pawn structure (normally I would show this position with no kings, but that is not a feature on chess.com). This pawn structure can come about from a wide range of openings, but mainly double king pawn, center counter and french defense.
Some examples of how this middlegame structure is reached...
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d4 exd4 5. e5 Ne4 6. O-O d5 7. exd6 Nxd6 8.Bb3 Be7 9. Nxd4 Nxd4 10. Qxd4
1. e4 e5 2. Nf3 Nf6 3. d4 Nxe4 4. Bd3 Nc6 5. dxe5 d5 6. exd6 Nxd6
1. e4 Nf6 2. Nc3 d5 3. exd5 Nxd5 4. Nxd5 Qxd5 5. Nf3 Nc6 6. d4 e5 7. Be3 exd4 8. Nxd4
1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 dxe4 5. Nxe4 Be7 6. Bxf6 Bxf6 7. Nf3 O-O 8.c3 Nd7 9. Bd3 e5 10. Nxf6+ Qxf6 11. dxe5 Nxe5 12. Nxe5 Qxe5+ 13. Qe2
Really the possibilites are endless as this is one of the most common middlegames in chess, true sometimes there is a slight pawn difference here or there, but I am talking about positions in general with an open d & e files for both players.
The golden rule for the open middlegame structure is going to be quality piece placement. You can acheive this by following the basic rules of development, Knights in the center, King safely castled, Rooks on open files, etc.
1. Since we have a symmetrical postion every little difference counts and the player who falls behind in development or quality of development can often be blown off the board or suffer endlessly in a worse ending. Think of it as two mirrored clones engaged in battle, whoever flinches first reveals himself to the true victor.
2. Often times a weakness in the remaining pawn structure, such as doubled pawns or backward pawns, can decide who has the advantage.
3. I will also add that the bishops will usually be superior to the knights in open middlegames due to their longer scope. Having the two bishops when your opponent does not can often be a upperhand.
Let us look at a typical example where white has a lead in development and attack. Black defends by going into an endgame, but has to make some weakness to get there...