Hungarian Defense - 4.d4 Exd4

4.d4 Exd4

White's best response is 4.d4 when 4...exd4 5.Nxd4 would transpose into a variation of the Scotch Game that gives White a spatial advantage. Weaker is 5.c3, hoping for 5...dxc3?! 6.Qd5!, after which Black resigned in the game Midjord–Scharf, Nice Olympiad 1974 (though Black could have tried 6...Nh6 7.Bxh6 0-0 when 8.Bc1?! Nb4 9.Qd1 c2 wins back the piece, so White should play 8.Bxg7 Kxg7 9.Nxc3 with advantage.) However, 5...Na5!, recommended by Chigorin, forces White to give up the bishop pair with 6.Qxd4 or sacrifice a pawn.