Two Knights Defense, Fritz Variation

The Fritz Variation replaces the usual 5...Na5 of the Polerio Defense with 5...Nd4. Black still gives up a pawn but puts the knight on a central square, where it covers b5 and c6 and creates tactical chances against White's uncoordinated pieces. The knight's weakness is that a c3 pawn push hits it, and it has few safe squares to retreat to, so it is often exchanged or offered as a sacrifice. The line is closely related to the Ulvestad Variation, 5...b5, and the two frequently transpose.

The usual reply is 6. c3, which challenges the knight at once. The next most common choice, 6. d6, returns the pawn to disrupt Black's development, but Black scores very well against it in online play. 6. O-O is a quieter option. The positions are wild and forgiving to neither side. The engine gives White a slight edge, yet Black wins more often than White in Lichess games.