King's Indian Defense: Fianchetto Variation, Debrecen Defense

A flexible and solid chess opening for Black, focusing on a strong pawn structure and counterplay on the queenside.

The opening in question is a popular and flexible choice for Black, which aims to create a solid pawn structure and counterplay on the queenside. Black allows White to establish a strong pawn center with pawns on d4 and c4, while focusing on developing their pieces harmoniously. The fianchettoed bishop on g7 is a key feature of this opening, as it exerts pressure on the long diagonal and can support a potential pawn break with e5 or c5.

In this variation, Black delays the development of their light-squared bishop, instead opting to develop their knights first. This can lead to a slower, more strategic game, as both sides maneuver their pieces and look for the right moment to strike. White typically aims to expand on the queenside with moves like b4 and c5, while Black looks for counterplay with moves like a6 and b5.

The defense is named after the Hungarian city where it was first played in a tournament in 1925. It has been employed by many top-level players, including former World Champions Anatoly Karpov and Garry Kasparov. The opening is known for its flexibility and solidity, making it a popular choice for players of all levels.