Borg Defense: Zilbermints Gambit is a chess opening with the ECO code B00, part of the Borg Defense family. It goes 1. e4 g5 2. d4 e5. White opens with 1. e4 (the king's pawn) and Black answers 1... g5. After 4 moves it is White to move. The lesson on the board explains every move of the line and lets you play it yourself; it is free.