King's Indian Defence, Four Pawns Attack


The Four Pawns Attack in the King's Indian Defence is a chess opening that begins with the moves:
White immediately builds up a large in order to gain a advantage. Black first develops his pieces, then tries to attack White's centre by means of the pawn advances...e7–e5,...c7–c5 or...f7–f5, depending on circumstances.
This formation has never attracted serious interest in high-level play, although Alexander Alekhine used it three times in the 1924 New York City tournament with a score of +1−0=2. Danish grandmaster Bent Larsen also occasionally experimented with the Four Pawns Attack.
The main variations of the Four Pawns Attack are:
The relevant Encyclopaedia of Chess Openings codes are E76 through E79.

The main line

The main line of the Four Pawns Attack after 6...c5 7.d5 continuing 7...e6 8.Be2 exd5 9.cxd5 now gives Black a choice of the old main line with 9...Re8 or the new main line with 9...Bg4.

Old main line with 9...Re8

Highly tactical possibilities abound in which the critical position occurs after 10.e5 dxe5 11.fxe5 Ng4 12.Bg5, a position which is perhaps better avoided by Black. After 12...Qb6 13.0-0 Nxe5 14.Nxe5 Bxe5 15.Qd2 Bf5 white was not able to achieve any significant advantage.

New main line with 9...Bg4

A common-sense move with the idea of exchanging the bishop for the knight and taking the energy out of White's e5 attacking plan. The development of the bishop also frees Black's queenside for smooth development and active play.
Invariably, development continues with 10.0-0 Nbd7 when White faces the possibly of the bishop with h3 or delaying with Re1 first. In the game Jesus Nogueiras–Garry Kasparov, White opted for the immediate kick, 11.h3 Bxf3 12.Bxf3 Re8 in a game that was eventually drawn.

White varies on move 7, 8 or 9

Having similar ideas to the Benko Gambit, this b5 push remains uncharted. After 8.cxb5 8...a6, White has choices between the possibility of taking the a-pawn, or supporting the pawn on b5. The more common response is to support with 9.a4.

The modern alternative 6...Na6!?

Black first develops one additional piece before reacting in the centre. The idea is to bring in the push e7–e5 instead of the main line c7–c5. This is a gambit in which Black hopes to take advantage of the slight underdevelopment of White forces in order to win back the sacrificed pawn or to directly attack the white king. The move...Na6 is designed post on c5 in order to attack the e4-pawn. An important difference between this move and Nbd7 is that Na6 does not block the queenside bishop.
After the normal 7.Be2, Black must immediately unleash 7...e5!? when White has several possibilities, but only a capture on e5 is assumed to make sense:
Black can also vary with 5...c5, electing to strike at the White centre before castling and discouraging any 6.e5 ideas from White. Teimour Radjabov, perhaps the leading contemporary practitioner of the King's Indian Defence, has been known to play this line. If 6.dxc5, Black can answer with...Qa5, effectively forking the pawns at e4 and c5, regaining the material with a stronger centre and a lead in development. Generally, Black will follow up with 7...Qxc5, preventing White from castling at least temporarily and taking control of the sensitive g1–a7 diagonal, given that White has moved his f-pawn. If after 6...Qa5 White plays the materialistic 7.cxd6? then Black has 7...Nxe4 with advantage.