4.d4 exd4 5.O-O: back to the centre is variation 4 of 6 in the Two Knights Defence course, a beginner opening course for Black (ECO C55). It runs 24 moves and begins 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d4 exd4 …. White opens the centre and castles, giving a pawn. Black takes on e4, then gives the piece back with ...d5. The queen steps to a5 with a pin, Black castles long, and the game is balanced. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. e4 – White takes the centre.
1... e5 – Black claims an equal share.
2. Nf3 – White develops and attacks e5.
2... Nc6 – Black defends e5.
3. Bc4 – The bishop aims at f7.
3... Nf6 – The Two Knights Defence: Black attacks e4.
4. d4 – White opens the centre at once.
4... exd4 – Black takes the pawn.
5. O-O – White castles and offers a pawn for quick development.
5... Nxe4 – Black takes a second pawn. This is the simple and safe answer.
6. Re1 – The rook attacks the e4 knight and pins it to Black's king.
6... d5 – The key move. Black gives the piece back to finish development.
7. Bxd5 – White takes the d5 pawn. If the queen takes back, Nc3 will hit the queen and the e4 knight.
7... Qxd5 – Black takes back. For the moment Black is a piece up.
8. Nc3 – The knight attacks the queen and the e4 knight.
8... Qa5 – The queen steps aside and pins the c3 knight to the e1 rook.
The lesson goes on for 8 more moves, each with its explanation.
chessGM