Nimzo-Indian Defense: Classical Variation, Noa Variation is a chess opening with the ECO code E37, part of the Nimzo-Indian Defense family. It goes 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 d5 5. a3 Bxc3+ 6. Qxc3 Ne4 7. Qc2. White opens with 1. d4 (the queen's pawn) and Black answers 1... Nf6. After 13 moves it is Black to move. The lesson on the board explains every move of the line and lets you play it yourself; it is free.
The moves
1. d4 – White plays the pawn to d4
1... Nf6 – Black plays the knight to f6
2. c4 – White plays the pawn to c4
2... e6 – Black plays the pawn to e6
3. Nc3 – White plays the knight to c3
3... Bb4 – Black plays the bishop to b4
4. Qc2 – White plays the queen to c2
4... d5 – Black plays the pawn to d5
5. a3 – White plays the pawn to a3
5... Bxc3+ – Black takes on c3 with the bishop, giving check
6. Qxc3 – White takes on c3 with the queen
6... Ne4 – Black plays the knight to e4
The line goes on for 1 more moves; the lesson shows them all.
In chessGM's opening book this position continues with 7... c5.
About the Nimzo-Indian Defense
After 1.d4 Nf6 2.c4 e6 3.Nc3, Black pins the knight with 3...Bb4. Black fights for e4 with pieces instead of pawns.
Black is often happy to play ...Bxc3 and give White doubled c-pawns.
In return White gets the two bishops and should open the position for them.
Black uses ...c5, ...d5 or ...b6 with ...Bb7 to control the light squares.
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