Nimzo-Indian Defense: Sämisch Variation, Keres Variation is a chess opening with the ECO code E25, part of the Nimzo-Indian Defense family. It goes 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 d5 5. a3 Bxc3+ 6. bxc3 c5 7. cxd5 Nxd5 8. dxc5. White opens with 1. d4 (the queen's pawn) and Black answers 1... Nf6. After 15 moves it is Black to move. After the last move White is a pawn ahead in material. 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. f3 – White plays the pawn to f3
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. bxc3 – White captures on c3 with the b-pawn
6... c5 – Black plays the pawn to c5
The line goes on for 3 more moves; the lesson shows them all.
In chessGM's opening book this position continues with 8... Qa5.
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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