Check this article out about Master Chan, written by Alan Orr while interviewing Mark Wiley:
(URL of the full story here: http://www.alanorr.co.uk/htdocs/articles/markwIleyinterview.html)
Mark Wiley:
“The next encounter concerns Hsin-I Liu Ha Ba Fa Kung-Fu Master David Chan. I have always been interested in the internal aspects of Kung-Fu, and have studied Qigong for many years in many countries. However, until eight or so years ago, I had yet to meet a master whose internal skills were high enough to actually demonstrate them on me with effect. (It is easy to do so with one’s own students!). I was talking with Alex Co one day in Binondo, Manila’s Chinatown about this, and he said there was a master I must meet, as his fajing was superior to most. David was kind enough to come by Alex’s office where we were and talked for several hours on internal power, zhan zhuang, and fajing skills. But I really needed a physical demonstration, and one was set for that evening. Alex and I went to David’s home and there we were also met by Tony Diego and Tom Dy Tang. The first thing David did was to allow me to strike him anywhere on his body with full force. This is did with interest and (dare I say!) a bit of pleasure. Round kicks to the legs, upper cuts to the ribs and kidneys, all with no effect! And all the while David just chuckled and spoke about his training methods! Next, he asked me to try and move him from his stance. I knew I had him here, having been involved in many such demonstrations and knowing how to push to break one’s center of balance. Not only was I unable to budge David from his stance, but he was able to walk me back into the wall! Next, he stood on one leg and asked us all to try and push him back off balance. I was first in line, and behind me was Alex Co, Tony Diego and Tom Dy Tan. We four at once all tried to push him off his stance, but with no luck! He then was able to send our energy back at us and we all fell over off balance!Round four involved David using two fingers from each hand and with his fajing, sending me flying several feet in the air and more than ten feet back into the concrete wall which provided a “cushion” to my fall! I was so very impressed with David Chan’s skill and ability to demonstrate fajing on a stranger who was well versed in the arts, that I went on to study with him the methods of zhan zhuang standing qigong practices and iron body training. I was then fully convinced of the existence and use of such esoteric and hard-to-find skills, that I continue practicing them to this day.”