Omega-Delta Gambit

The Omega-Delta Gambit arises when Black answers the King's Indian Attack move order 1. Nf3 d5 2. g3 with 2...e5. The advance leaves the e-pawn unprotected against the knight on f3. Black is betting that White's fianchetto is too slow to punish an immediate grab for the center, and hopes to gain time against the knight if it captures. In return Black obtains the classical d5-e5 pawn duo, the very center the King's Indian Attack normally invites Black to occupy more gradually. It is one of the rarer replies to 2. g3.

White has three main replies. The most popular is 3. Bg2, which ignores the pawn and continues the setup, usually transposing to positions where Black has a free hand in the center. Taking with 3. Nxe5 is the second choice, and it gives White the best practical results. 3. d3 is less common and prepares to challenge the center with e4. Engines consider 3. Nxe5 the strongest move and give White a clear advantage, so the gambit is mainly an offbeat surprise weapon in fast online games, where White scores well.