An In-Depth Look at Single Sticking Hands - Grandmaster Chu Shong Tin 1991

This footage is very valuable and worth a lot of study. I hope viewers find it helpful.
The majority of students I have seen are not capable of performing Single Sticking Hands to a satisfactory level. Students would do well to watch and analyse this detailed video where Grandmaster Chu teaches the subtleties of Single Sticking Hands. If you put a long period of practice into checking your Single Sticking Hands and making sure everything is perfect you will be sure to make a large improvement in your Wing Chun skills.

Two things to note:
1. Focus more on what Sigung is teaching and the corrections he is making to the students. He is not necessarily always demonstrating the perfect technique when he is feeding as the training partner.
2. I recommend people do not hyper-fixate on the discussion about whether angles of the Fook sau or Bong sau open or close. They may generally open or generally close but it is not always absolute. Sigung himself does not actually confirm what Graham and the others are discussing. You will notice that at some points when demonstrating Sigung’s Bong Sau angle actually opens when he is knocking students backwards during Single Sticking Hands. It is important to understand that it is the force which is always going forwards, not necessarily the arm. A spring may be compressed backwards yet its force remains forwards at all points in time.

Below is a brief summary of some of the points that Sigung Chu Shong Tin is making throughout the video:
Keep the fingers pointing and the palm facing the target when performing the Palm Strike from the Tarn Sau.
Maintain the sinking/settling/releasing of the shoulder into the elbow (Zhang Dai Lik) at all times.
Keep the arms connected to the stance/body.
Point the fingers forwards when in Low Bong Sau and Bong Sau
Keep the force across the whole forearm equal (this is a natural consequence of correct triangulation)
Maintain Herng (forward force, aim, triangulation, pointing) towards the opponent at all times

Many of these points are connected – for example, if you are maintaining the Zhang Dai Lik (Shoulder sinking into Elbow), and pointing the fingers in the Low Bong Sau, it will be far easier to maintain Herng (forward force) and to keep the force across the forearm equal.