Glek System

The Glek System, 4. g3, is a modern treatment of the Four Knights Game associated with Igor Glek. White does not commit the light-squared bishop to b5, c4 or d3. Instead White prepares Bg2, usually followed by d3, to build a King's Indian Attack style setup in which the bishop works on the long diagonal and supports e4. This keeps more tension than the symmetrical main lines and tends to give a less drawish game. The position can also arise from the Konstantinopolsky Opening after 1. e4 e5 2. Nf3 Nc6 3. g3 Nf6 4. Nc3.

Because 4. g3 does nothing to restrain Black in the center, Black has several good replies. The most frequent is 4...Bc5, with 4...Bb4 and 4...d5 next. The move 4...d5 strikes at e4 before the bishop reaches g2. Analysis credited to Pinski holds that both 4...Bc5 and 4...d5 equalize. The sharper 4...Nxe4, a Halloween Gambit-style capture, is among the engine's preferred moves and has been tried by grandmasters, including in two games between Ilya Smirin and Bartłomiej Macieja. Results on Lichess are almost exactly even, and engines also assess the position as balanced.