Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...d5/5. exd5/5...Nd4

=Two Knights Defence:Fritz variation= 5 ... Nd4 The Fritz Variation of the Two Knights. This move put the Knight in a central position  and can lead to a number of tactical possibilities, however the Knight is always vulnerable to being attacked by a c3 pawn and then having few squares to retreat so the Knight is often exchanged or sacrificed.

Theory table

 * 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Nd4