Two Knights Defense, Ulvestad Variation

The Ulvestad Variation replaces the usual 5...Na5 with 5...b5. The pawn offer aims to lure the bishop away from c4, where it guards d5 and eyes f7, so that Black can recapture on d5 with the queen. American master Olaf Ulvestad proposed the move in Chess Review in 1941, objecting that 5...Na5 sends the knight offside. Accepting with 6. Bxb5 is the most common reply online, but 6...Qxd5 hits both the bishop and g2, and Black scores well. The exchange 6. dxc6 bxc4 is considered to equalize. The retreat 6. Bf1 is regarded as the strongest answer. It covers g2, and 6...Qxd5 is met by 7. Nc3 with tempo, so Black usually continues 6...Nd4, transposing to the Fritz Variation. Ulvestad recommended 6...h6, but after 6. Bf1 h6 7. Nxf7, the Kurkin Gambit, 7...Kxf7 8. dxc6 favors White. The play is sharp and leaves little room for error, and the engine gives White a slight edge.