Vos Gambit

The Vos Gambit arises when Black answers 1. Nf3 with 1...d6, the Pirc Invitation, and then meets 2. d4 with 2...e5 instead of the usual 2...Nf6. It is one of the few independent tries in that move order. The point is to strike at the center at once, hoping that White's acceptance costs time. The e5 pawn is attacked by both the d-pawn and the knight but defended only by the d6 pawn, so the offer is a genuine one. The engine rates the position as a large advantage for White and names 3. dxe5 as a top choice. Opening references treat the gambit as dubious.

In practice White most often declines with 3. e4. This transposes into the Philidor Defense, giving Black a known structure without any material deficit. The capture 3. dxe5 is the main way to test the gambit. The quieter 3. e3 and the developing 3. Bg5 are seen less often, and White scores particularly well after 3. Bg5. Despite the engine's verdict, overall results on Lichess are fairly close, which reflects how rarely the extra pawn is converted cleanly at club level.