The gaan sao is a hand move that reminds of a plough. It moves downwards following the orientation line.
encyclopaedie
As kwan sao, we describe a move composed of a tan sao and a deep bong sao. It is a defensive as well as an offensive move.
What we describe as jum sao is the sinking elbow. This minimal move protects the under part of the upper body like belly and liver.