While visiting Master Stephen Hwa at his home in Florida, he knocked on the door of his second apartment and said, "have you eaten yet"? He then came in, sat down with me, and talked about Fajin. He told about the one-inch punch, "...all materials have a "time constant" in their elasticity ."
A time constant is the time that represents the speed with which a particular system can respond to change. It is typically equal to the time taken for a specified parameter to vary by a specific factor. In the DVD "Tao of Martial applications," he hit Tom Kostusiak with a one-inch punch. It hit with so much force, so much speed it created a "time delay "..." (irrespective of the "time constant").
The Barrie Ryuesi Karate Club posted a discussion and video of Master Hwa's demonstration on their web page of fajin. I discuss this with them here, and their comments are in the quotations, and I am JR. Thank you, Barrie Ryuesi Karate.
Barrie discussion
"Here is quite a good and believable demonstration of fajin, or the explosive delivery of internal energy, by Stephen Hwa, who teaches taijiquan at the University of Buffalo and in Fairport, New York."
JR: Master Hwa does not still teach at the University of Buffalo or Fairport, but he is at info@classicaltaichi.com. Presently, he teaches in Pompano Beach, Florida, where (while in the springtime of his life) he enjoys Florida's perpetual springtime.
Barrie: "He shows the "one-inch punch" made famous by Bruce Lee (see video link), who at the 1964 Longbeach championships knocks someone into a chair, without any windup. His fist started an inch away from the target.
JR: I think it is a matter of opinion whether Bruce Lee does the punch "without any windup ."You will need to watch the video link: Notice his fist starts close to the man's chest (near solar plexus?), and you see him touch the man's chest a couple of times before delivering power. If you look carefully, you can see the man sway gently as Bruce's fist makes contact on a couple of occasions. As he touches the man's chest, Bruce adjusts his foot stance with his back foot pointing almost 90 degrees out.
Barrie: "Master Hwa shows how it is possible to generate this power using the taiji "hollow-fist punch." He explains that other people have recreated this but use external" or purely muscular power. In his demonstration, he has his "hollow fist with pointed knuckles" pressing against the pad held to another person's midsection. His student Sifu James Roach holds onto his bicep and forearm to feel his muscular contraction.
JR: With the "hollow-fist punch," the reasoning is the same as why he maintained a relaxed arm. Bruce's fist, however, is clenched tightly, and the arm extends almost entirely. With such a clenched fist, the arm cannot maintain relaxation. Try this yourself, clench the fist very tightly, and notice its effect on your arm and body. The use of muscular power is evident in Bruce's punch. With such preliminary muscle tension, it is "external" power. It is what Master Hwa called a precursor to "ordinary force ."When the punch is delivered, one can see him pushing from the back foot. Force generated from external limbs such as arms and legs has a much longer duration and cannot be compacted into such a burst as possible with a "hollow fist" and relaxed arm.
Barrie" With seemingly little effort, he knocks back the man holding the pad, who feels a sudden power surge. The man holding Hwa's arm says it is relaxed before and after the punch, with only brief tension as the power delivers to the opponent. Hwa explains that a tense arm will significantly reduce the force if the arm tenses before the power is delivered."
JR: The Barrie comment "knocks back the man" is more detailed than the appearance would have us believe. The detail is so because of Tom's body structure and Master Hwa's. Ideally, one has to have a better body structure than the receiver. Bruce Lee has a body structure incomparably better than the receiver who stands flat-footed with feet together. Master Hwa's body structure is poor, and Tom has a better structure. The "reaction force" (Newton's Law of action and reaction) will push Master Hwa back instead of Tom IF he had used "ordinary force ." He uses Nejin, which goes out like a whip with no tension that would be affected by the "reaction force ."After all, Newton cannot be wrong.
To explain this better, we refer to the term "Peng, " one of the 13 movements of Tai Chi. Peng has a significant component, an uplifting force for the most part. It lifted Tom partially off the ground, then a minor forward force (the knockback portion) knocked him back. In this case, M. Hwa's tight, compact and upright stance is advantageous as an utterly relaxed arm, and body absorbs the reaction force.
Tom did not receive all the "explosive" energy possible because of the pad. As Master Hwa demonstrated on an amateur boxer (familiar with body punches), even a force of reduced power with no pad collapses the receiver (Uncovering the Treasure pp.109).
The "tensing" of the arm starts at the split second the
hollow fist reaches the opponent and resistance closes it. Also, Bruce uses the whole fist, whereas Master Hwa forms the knuckles into an open fist. The analogy is like that of "holding a robin's egg". One can imagine that clenching the fist before impact or even during would crack the egg, would it not? The hollow fist has pointed knuckles not tightly held and it is designed to strike at soft tissue and not a bony part where it would hurt the fist.
The stiffening is a natural response to the feedback of a sensation of resistance. A side note to this is whether the opponent or target is like, or one might say, analogous to a "creampuff" or a "side of beef ."In the latter, the resistance will be instantaneous, thus providing immediate feedback to such a pronounced sensation of resistance. If "creampuff" like with no resistance, there will be little or no power delivery.
I had that discussion with Master Hwa, a Ph.D. chemical engineer (which got me interested) about terms like "time constant." My layman understands that all materials have a "time constant" in their elasticity. Well, in this case, the force is coming at Tom (as Master Hwa later says) with so much power and so much speed it creates a "time delay" (irrespective of the "time constant"?) in Tom's body going backward. Measuring how far the punch penetrates during and after the pad is really only about 2 or 3 inches of compact movement.
Regardless of that, it still penetrates Tom's body, and one might say completely. I call it an "implosion" on the inside of Tom's body instead of an "explosion" on the outside. It is a "spike" of power because, like a spike, the opponent's body has no chance to get away from the full force. He receives the whole force before his body moves back, so much for "pulling the punch."
One cannot get "internal discipline" and cultivate "internal energy," Fajin, by external movement, so one must learn from the Tai Chi form. In all fairness to Bruce Lee, he might have been pushing the opponent not to hurt him, thus diminishing his force. After all, he did not use a pad, and the potential for injury was great because his fist looked like it was spot on the solar plexus. Either way, you can come to your conclusions. I humbly hope I have provided some additional observations based on my experience as a practitioner/teacher of the art and as the individual who was lightly touching Master Hwa's arm.