Man sao is the searching hand. It serves as front line to take the first attacks of the opponent. The typical ving tsun guard position is man sao...
encyclopaedie
The jut sao is executed with the inner part of the wrist and serves as a preparation for further attacks like a punch or a fung hao.
Wu sao will be described as protecting hand. It is the last line of defense in front of the body, before the attack reaches it.
The gaan sao is a hand move that reminds of a plough. It moves downwards following the orientation line.