1...Nf6 2.Bb2 g6 is variation 5 of 6 in the Nimzo-Larsen Attack course, a intermediate opening course for White (ECO A01). It runs 19 moves and begins 1. b3 Nf6 2. Bb2 g6 3. e3 Bg7 4. Nf3 O-O …. Black puts a bishop on g7 to fight the b2 bishop. White develops, plays c4 and keeps the game flexible. After the centre opens, White's bishop on b5 hits the c6 knight. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. b3 – The Nimzo-Larsen Attack.
1... Nf6 – Black develops and blocks the long diagonal for a moment.
2. Bb2 – The bishop takes the long diagonal.
2... g6 – Black's most popular move. Black wants a bishop on g7 against the b2 bishop.
3. e3 – White opens the f1 bishop and keeps a firm centre.
3... Bg7 – The bishops face each other on the long diagonal.
4. Nf3 – White develops and covers d4 and e5.
4... O-O – Black castles.
5. c4 – White takes space and watches the d5 square.
5... c5 – Black takes space too.
6. Be2 – White gets ready to castle.
6... d5 – Black strikes in the centre.
7. cxd5 – White takes the pawn.
7... Qxd5 – Black takes back with the queen.
8. O-O – White castles.
8... Nc6 – Black develops the last knight.
The lesson goes on for 3 more moves, each with its explanation.