Kmoch/Gheorghiu 4.f3: ...d5 and ...Qa5 is variation 6 of 6 in the Nimzo-Indian Defence course, a advanced opening course for Black (ECO E20). It runs 22 moves and begins 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 d5 …. White prepares e4 with f3, Sämisch-style. Black strikes at once with ...d5 and ...c5, and the queen jumps to a5 to hit the weak c3- and c5-pawns while White's kingside is undeveloped. 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.
2. c4 – White gains space.
2... e6 – Prepares ...Bb4.
3. Nc3 – White prepares e4.
3... Bb4 – Pins the knight.
4. f3 – White prepares e4 with a pawn, so that the pin on c3 no longer matters.
4... d5 – The most principled reply: Black stops e4 by direct confrontation in the centre.
5. a3 – White forces the trade on c3.
5... Bxc3+ – Black takes, giving White doubled c-pawns.
6. bxc3 – White recaptures toward the centre.
6... c5 – Black adds pressure on d4 and prepares to open lines while White's kingside is undeveloped.
7. cxd5 – White resolves the tension before Black can take on c4 and leave White's doubled c-pawns isolated and weak.
7... Nxd5 – The knight recaptures centrally and attacks the c3-pawn.
8. dxc5 – White breaks up Black's pressure on d4 and grabs a pawn.
8... Qa5 – The queen hits c5 and c3 at once; Black will regain the pawn.
The lesson goes on for 6 more moves, each with its explanation.
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