Chess Opening Theory/1. d4/1...Nf6/2. c4/2...e5/3. dxe5/3...Ng4/4. e3/4...Nxe5/5. Nh3

= Shereshevsky Variation =

5. Nh3
White plans on putting his knight on f4, to prevent d5 by black. Additionally, he'll fianchetto his dark squared bishop to b2.

Theory table
1. d4 Nf6 2.c4 e5 3.dxe5 Ng4 4.e3 Nxe5 5.Nh3