Danish Gambit, Horowitz Defense
People have been trying to "refute" the Danish Gambit for a long time. A notable attempt was made by I.A. Horowitz in the 1960s. He proposed a novel setup for Black in the Dansih Gambit accepted. This setup would normally have been achieved after 5...d6, but Horowitz recommended 5...c6 first. The Horowitz Defense hasn't been played very much since that time, and no one has ever resolved the question of whether it's really a "refutation" or not. In the Danish Gambit Accepted position after 1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2, Horowitz recommended the new move 5...c6!?. The intent is to play ...d6, ...Nd7, ...Nc5 and ...Be6. In this way Black will eliminate the powerful White c4 Bishop, and construct a defensive pawn formation on the Queenside. White's lack of Queenside pawns makes it hard to stop this plan.