King's Indian Attack, with Bf5 is a chess opening with the ECO code A07. It goes 1. Nf3 Nf6 2. g3 d5 3. Bg2 c6 4. O-O Bf5 5. d3 h6 6. c4 dxc4. White opens with 1. Nf3 (the Zukertort/Réti knight move) and Black answers 1... Nf6. After 12 moves it is White to move. After the last move Black 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. Nf3 – White plays the knight to f3
1... Nf6 – Black plays the knight to f6
2. g3 – White plays the pawn to g3
2... d5 – Black plays the pawn to d5
3. Bg2 – White plays the bishop to g2
3... c6 – Black plays the pawn to c6
4. O-O – White castles kingside
4... Bf5 – Black plays the bishop to f5
5. d3 – White plays the pawn to d3
5... h6 – Black plays the pawn to h6
6. c4 – White plays the pawn to c4
6... dxc4 – Black captures on c4 with the d-pawn
About the King's Indian Attack, with Bf5
White sets up Nf3, g3, Bg2, O-O, d3 and later e4: a King's Indian with colours reversed. It is an easy system against almost anything.
White plays Nbd2, e4 and often e5 to gain kingside space.
With a pawn on e5, White attacks with Nf1, h4 and Ng5 or Nh2-g4.
Black usually expands on the queenside with ...c5, ...b5 and ...b4.