Dear chess friends,
Every 1.d4 chess player must find a reliable weapon against the King's Indian Defence. Even though we live in a modern time where chess is dominated by computer programs, this opening gains in popularity. The arising positions are extremely complex and double-edged. That is the reason why this is the favourite opening of creative players like Kasparov, Radjabov and Nakamura. Their games are rich of brilliant attacks against the White king. Of course, chess knows great anti-King's Indian players, too. When looking back at the past, we can mention the names of great players like Petrosian and Korchnoi, while nowadays Tomashevsky and Kramnik are the first players that come to our mind. My suggested repertoire against the King's Indian is based on one of the ideas of Vladimir Kramnik. In his game against Nakamura, played in London, in 2014, he played an extremely interesting novelty that made me change my mind about the Petrosian variation. Of course, within the framework of our course, I am going to cover all the deviations in order to construct a complete repertoire for White.
1.d4 Kf6 2.c4 g6 3.Kc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 (6...Na6 is a possible deviation for black. My suggestion here is 7.Bf4, but for more details, please take a look at game 2.)
7.d5! This move marks the beginning of the Petrosian system.
The position in the centre is stable and now the plans are clear - White is planning to organize a pawn expansion on the queenside, whereas black is going to undertake active actions on the kingside. The battle is very complex and every single move is of a great importance.
7...a5 This is the main and most popular continuation. Black's idea is to slow down White's queenside pawns. At the same time, in such kind of positions, the idea to generate pressure on the "e4" open by the manoeuvre Na6-c5 is an option. However, the move 7...a5 is not the only choice for black.
Let's have a look at his other possibilities.
7...Nbd7 Here, my preference is for the move 8.Be3 -game 2
7...Na6 is another move which leads to unpleasant positions for Black after 8.Nd2 - game 4
8.Bg5 In such kind of positions. White develops his queenside attack in the following way - Nd2, a2-a3, b2-b4, c4-c5 followed by Nc4. However, if White plays 8.Nd2, then the bishop on "c1" will be out of play. That's why we should develop our bishop, before making knight manoeuvres.
8...h6 Black has no alternatives here, (because after: 8...Na6 White could play 9.Nd2 with an excellent position. Everything is ready for the execution of the above-mentioned plan.)
9.Be3! The choice of Kramnik
I have always been interested in this continuation which leads to very sharp play with mutual chances. In this variation, Black is under pressure and very often must find only moves, in order to survive.
More positional way to continue is the main line 9.Bh4 Na6 10.a3 Bd7 11.Rb1 Qe8 12.b3 Nh7 with mutual chances.
You can see in a sample the game which inspired me to love this variation: Kramnik-Nakamura 
You can see the game in the viewer below: