Big loss.
A very cool and interesting guy.
Given the level of respect he had for Bruce Lee, and how much Bruce influenced him, I'm not surprised that he created his own hybrid style/discipline.
He said several times that Bruce expanded a great deal on his knowledge of the mental/philosophical/discipline part of martial arts, and that the physical prowess side could never make a person truly a master. Bruce was correct in that there will always be someone who is stronger, quicker, and faster than you are.
Death will likely get us all, some before others, unless we are in that spiritual point in time. But although I didn't follow him closely, I thought Chuck was in better health. I expected him to make it into his nineties or better. Too bad.
