I'm just curious because I just unearthed an old meditation book of mine and I just now realized it has a section on kumbhaka and found that it uses the exact same locks/holds as what ChNN teaches and has a really decent explanation of how they work in a very concise but detailed way that makes me want to practice again, but the explanation for it is completely different.
This book's teachings are supposedly from Himalayan origin oral transmission, so maybe it is actually the same method but fell into a non-Buddhist lineage or something. I guess it is Kundalini Yoga which is being taught in this book.
They appeared to have completely different rationale for the same exact method. That is, the breathing and the locks are the same, but ChNN has the explanation about 'karmic breaths' and the need to control your breath because its the reason you are in samsara and this other book, in contrast, just explains how the different chakras develop and work and how by using the holds and breathing you can direct the kundalini up and experience kundalini awakening beyond your personal kundalini system which is basically functioning fine for a regular human being, if a bit dormant, but the awakening allows you to see beyond your personal awareness and know the "cosmic" kundalini (or words to that effect).
I can't think of a great analogy, but it struck me a little like one person saying running is an important exercise for cardiovascular health and another person saying running is an important exercise to keeping our body limber and increase your metabolism; both people are saying you must run, but for different reasons. Both are exactly the same method (running), but as you run you have a different reason in mind. (Yes, you can say that the method is different due to the visualizations employed in ChNN's method, but when I took classes on it, the visualization wasn't really emphasized much and, frankly, I couldn't get the hang of visualizing, holding, breathing, counting and snapping all at once, so what suffered most was the visualization, as I tried to keep mindful of the rhythm... I'm not a great visualizer, anyway, and I have little belief or faith that it is very important, to be perfectly honest. Namkhai Norbu himself seems to de-emphasize its importance, too.).
This is the book:
http://www.amazon.com/Meditate-Using-Ch ... 0971455805
I am curious if anyone has learned kumbhaka while practicing Kundalini yoga and then learned it from Namkhai Norbu and found it was the same thing but it somehow had a different result due to the visualization.