I would have to agree. I am taking Ki Aikido so I have begun to truly understand what ki is (as an aside ki and chi are not the same thing). Ki is everything, the energy that connects each thing to every other time. The reason it is used in several martial arts (aikido uses it the most of any art) is because when you are able to extend ki you are aware of not only any opponents but also of yourself. When you can do that you are able to prepare and execute the moves necessary to stop any attacks and turn them back around on your attacker.