many and various (in the yip chun lineage) what im saying in the overall picture is that in my experience taking into account that different people have different and varying skill sets the wsl system is the most practical for me.Put it another way name a Yip chun top student that would stand up to chi sau with PB for example and i may see a pig that flys, and yes i know chi sau is an exercise but you know when you can better someone at it!
cheers Jim