King's Indian Defense: Orthodox Variation, Positional Defense, Closed Line

The King's Indian Defense: Orthodox Variation, Positional Defense, Closed Line is a solid and flexible chess opening that leads to a rich middlegame with chances for both sides.

The opening is characterized by a pawn structure in the center, with Black allowing White to establish a strong pawn presence. Black's plan is to counterattack on the kingside, using the fianchettoed dark-squared bishop and the knight on f6 as key attacking pieces. White, on the other hand, aims to expand on the queenside and create weaknesses in Black's position.

In the Orthodox Variation, White develops the light-squared bishop to e2 and castles kingside, while Black plays e5, challenging the central pawn structure. The Positional Defense involves Black's knight being developed to d7, supporting the e5 pawn break and potentially preparing for a later f5 pawn break.

The Closed Line refers to the pawn structure after White plays d5, closing the center and solidifying their space advantage. This pawn structure often leads to a slow, maneuvering game, where both sides need to carefully plan their piece placement and pawn breaks.

This opening is popular among players who enjoy complex middlegames and are comfortable with long-term strategic planning. It has been employed by many top-level players, including former World Champions Garry Kasparov and Anatoly Karpov.