4.Nc3 Bb4: against the Kasparov Variation is variation 5 of 5 in the Queen's Indian Defence course, a advanced opening course for Black (ECO E12). It runs 24 moves and begins 1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. Nc3 Bb4 …. After 4.Nc3 Black pins the knight with 4...Bb4, as in the Nimzo-Indian. When White pins back with Bg5, Black breaks the pin with ...h6 and ...g5. The knight lands on e4 and Black gives the bishop for the c3 knight. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. d4 – White takes the centre.
1... Nf6 – Black develops and watches e4.
2. c4 – White gains space.
2... e6 – Black opens the f8 bishop.
3. Nf3 – White develops and avoids the pin on c3.
3... b6 – The Queen's Indian. The bishop will fight for e4.
4. Nc3 – White develops and supports a push to e4.
4... Bb4 – Black pins the knight, just like in the Nimzo-Indian. Now e4 is hard for White to reach.
5. Bg5 – White pins Black's knight in return.
5... Bb7 – Black develops and keeps an eye on e4.
6. e3 – White supports d4 and opens the f1 bishop.
6... h6 – Black asks the bishop where it wants to go.
7. Bh4 – White keeps the pin.
7... g5 – Black breaks the pin by force. The pawns move, but Black's king can wait in the centre.
8. Bg3 – The bishop goes back.
8... Ne4 – The knight jumps to e4 and attacks the c3 knight a second time.
The lesson goes on for 8 more moves, each with its explanation.
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