The Geller/Tolush Gambit (1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5 e4) has become enormously popular as a combative way for White to battle the solid Slav Defense, as White gives up the c-pawn for control of the center. The main ideas of the gambit was worked out by GM Alexander Tolush in 1947, and he played it against World Champion-to-be Vassily Smyslov during the USSR Championship of that year. But it was his fellow Soviet grandmaster (and noted theoretician) Efim Geller who worked the most to establish the gambit as a respectable opening by playing it consistently and finding many key improvements for White.