4.Nc3 Bb4: the Four Knights is variation 6 of 6 in the Berlin Defence course, a advanced opening course for Black (ECO C49). It runs 22 moves and begins 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. Nc3 Bb4 …. White defends e4 with the knight, and the game becomes a Spanish Four Knights. Black copies White's set-up, trades on c3 and unpins with the queen. The knight goes from c6 to e6, and Black is solid. 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. Bb5 – The bishop attacks the defender of e5.
3... Nf6 – The Berlin. Black attacks e4.
4. Nc3 – White defends e4 with the knight. This is the Spanish Four Knights.
4... Bb4 – Black copies White and pins the c3 knight.
5. O-O – White castles.
5... O-O – Black castles too.
6. d3 – White defends e4 calmly.
6... d6 – Black does the same. The position is symmetrical.
7. Bg5 – White pins the f6 knight. This is White's most popular plan.
7... Bxc3 – Black takes on c3 and damages White's pawns.
8. bxc3 – White takes back toward the centre.
8... h6 – Black asks the bishop at once.
The lesson goes on for 6 more moves, each with its explanation.
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