The scissors gaan sao is to be considered equally as defensive or offensive move. It protects the whole upper body from waist to head.
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.