411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...Nf6/2. c4/2...g6/3. Nc3/3...Bg7/4. e4/4...d6/5. Nf3/5...O-O
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King's Indian defence E70 King's Indian defence → 5. Nf3
5. O-O
White has an expansive pawn trio which Black is planning on attacking. White must brace himself because Black's counteroffensive in the centre of the board is about to start with ...e5.
6. Be2 is far and away the main move. White prepares to castle, and prevents ...Bg4 from pinning the knight. Black then begins their counter-offensive.
A small number of sidelines include:
6. Be3 is the Larsen variation. The bishop may find itself under attack: 6...e5 7. d5 Ng4 8. Bg5 f6 9. Bh4 Nh6.
6. Bg5 is the Zinnowitz variation. 6...h6 7. Bh4 g5 8. Bg3 Nh5 and Black can collect the bishop pair if they choose.
6. h3 is more passive move that stops ...Bg4 from happening but without allowing a kingside castle. This leaves the King slightly more vulnerable.
Theory table
1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O
6
7
8
Be2e5
O-ONc6
d5Ne7
+/=
h3e5
d5Na6
Bg5Qe8
=
References
See also
King's Indian Defence