Four Pawns Attack
King's Indian Defense
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.f4 O-O 6.Nf3 c5 7.d5 e6
White's most ambitious try, grabbing maximum central space, though overextension can backfire.
Practice this lineThe idea
White builds the biggest center possible with 5.f4: pawns on c4, d4, e4 and f4. The price is development, because White has moved a lot of pawns and few pieces.
In this line, 5...O-O 6.Nf3 c5 7.d5 e6, Black attacks the center straight away, and the position often turns into a Benoni structure after ...exd5.
Plans for White
Develop with Be2 and O-O, then look for the e4-e5 break, which can drive away the knight on f6 and open lines toward Black's king. White's space is an advantage only while the pawns stay strong.
Plans for Black
Open the position before White completes development: ...exd5, ...Re8 to pressure e4, and queenside play with ...a6 and ...b5. The bishop on g7 becomes very strong once the center opens.
Watch out for
For White, overextending. Pushing e5 before the pieces are ready leaves the pawns weak, and Black's pieces can attack them from every side.
For Black, waiting too long. If White gets castled and plays e5 with the pieces behind it, Black's position can be swept away.