black creates a Fork Threat since if the white K takes the rook black goes nd4 and has a "Family Fork."
2) kd3 e4+ 3) kc4 rc2+
"Forced Positioning" has put white's King into a "King Fronted Line Attack."
4)nc3 bf6
White "Self Pins" and Black instigates a "Pin Attack."
5)qe4 rc3
Black is now material ahead.
