3...Bb4 4.Nd5: the jump to d5 is variation 6 of 6 in the Four Knights Game course, a intermediate opening course for White (ECO C46). It runs 20 moves and begins 1. e4 e5 2. Nf3 Nc6 3. Nc3 Bb4 4. Nd5 Nf6 …. Black develops the bishop with 3...Bb4. White jumps to d5, wins the two bishops and strikes in the centre with d4. After the queen trade White has the bishops, and Black's king cannot castle. 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. Nc3 – White develops and protects e4.
3... Bb4 – The bishop eyes the c3 knight, a defender of e4.
4. Nd5 – The knight jumps to the centre and attacks the b4 bishop.
4... Nf6 – Black develops and attacks the d5 knight.
5. Nxb4 – White takes the bishop and wins the two bishops.
5... Nxb4 – Black takes back.
6. d4 – White strikes in the centre and opens the c1 bishop.
6... d6 – Black protects e5.
7. a3 – White chases the b4 knight back.
7... Nc6 – The knight goes back to c6.
8. dxe5 – White opens the d-file.
8... Nxe5 – Black takes back with the knight.
The lesson goes on for 4 more moves, each with its explanation.
chessGM