Open up a dictionary. Or even use an online dictionary.
Look for a word, any word. For example, APPLE.
You get a definition of what APPLE is which is that apple is a round fruit with firm, white flesh, skin of green, red or yellow.
Then you are given context in which the word APPLE can be used. For example, peeling an APPLE, plucking from APPLE tree, making APPLE pie.
You are also given examples of how the word APPLE is used in sentences. For example, he took a bite from the apple. Or an apple fell on Newton’s head and enlightened him to the existence of gravity.
The Wing Chun SNT form is sometimes referred to as a dictionary form. So as a dictionary form we would expect to find defined techniques, the context in which the technique is used and example of how it is applied.
For example, Fak Sau is a strike with the blade of the palm (definition). The context in which it can be used is as a chopping attack to the throat. In terms of usage we can parry the opponent’s punch as we sit back and turn the body, followed by which we quickly sit forward and whisk our palm to strike the throat.
As a dictionary form we have thus learn Fak Sau in the following manner :-
a) What is Fak Sau? How does the movement go? What is the body mechanics of the arm movement when our body is kept facing squarely, allowing us to study the movement of the arm in isolation.
b) What is body turning? Why do we turn the body? What are the biomechanical actions? How much should we turn the body? How does turning the body assist in executing the Fak Sau technique?
c) Why do we sit back and then forward? What stances are used here? What are the body mechanics? How does shifting the stance add to power generation?
So when you consider the above you can see why the Siu Nim Tao (or Siu Lin Tao in some Wing Chun styles) is a dictionary form. In the modern variant factors (b) and (c) have been eliminated. Instead, factors (b) and (c) are studied in Chum Kiu and Biu Jee but not in as clear a manner as when they are delineated within Siu Nim Tao.
When factors (a) to (c) are studied within Siu Nim Tao students can then go on to Chum Kiu and Biu Jee and examine the key lessons of each form instead of trying to seek that which is supposed to be in Siu Nim Tao in the first place but revised out.
I would say revising the form to a shorter version is not necessarily a bad thing. But when this shorter version is not taught with an understanding of how to use a shorter form then a lot of things will get lost in the transition from longer to shorter form.
So the basics learned in Siu Nim Tao are then practiced in Chum Kiu. As designed there are no new techniques in Chum Kiu that have not been learned in Siu Nim Tao. What is found in Chum Kiu are but the techniques of Siu Nim Tao rearranged to teach the application of the principle of seeking bridge as a fighting strategy.
By comparison, learners of the modern versions of Chum Kiu will now be learning how to step, turn body and seek the bridge. They are only given short samples of how to apply some of the techniques of Siu Nim Tao to carry out the strategy.
When you consider the prevalent learning in this limited manner it is not surprising that modern Wing Chun practitioners can learn an entire spectrum of techniques at the Siu Nim Tao level but when they try to apply what they learn in Chi Sau they are only able to use very few techniques instead of using all the techniques as they should. If Wing Chun is a smartly designed art it would have gotten rid of techniques that are not practical or hardly used. But that is not the case though in practice this seems to be it. That students or even teachers fail to see this learning logic is ironic.
At this point we are only considering the basics that should be learned. We have not considered that Wing Chun in the older variants also teach case studies relating to the application of techniques. An example would be how to apply the techniques to counter an opponent using locks.
On another level, the students are also taught to refine they way they move, the way they apply the techniques and so on. The practice of the weapons is meant to enhance and change the way the body is structured and mobilized. In today’s learning of the weapons these “it” factors are missing. They also happen to be indicators as to whether a person has learned the weapons properly.
The Wing Chun system is designed to be learned in a certain way. When practiced following the road map you should acquire certain body characteristics that allows you to apply the techniques in line with the strategy, principles and power generation methods of the system.