He often used water as an analogy for describing why flexibility is a desired trait in martial arts.
Water is infinitely flexible.
It can be seen through, and yet at other times it can obscure things from sight.
It can split and go around things, rejoining on the other side, or it can crash through things.
It can erode the hardest rocks by gently lapping away at them or it can flow past the tiniest pebble. Lee believed that a martial system should have these attributes.
JKD students reject traditional systems of training, fighting styles and the Confucian pedagogy used in traditional kung fu schools because of this lack of flexibility.
JKD is claimed to be a dynamic concept that is forever changing, thus being extremely flexible.
"Absorb what is useful; Disregard that which is useless" is an often quoted Bruce Lee maxim.
JKD students are encouraged to study every form of combat possible.
This is believed to expand one's knowledge of other fighting systems; to both add to one's arsenal as well as to know how to defend against such tactics.
Bruce Lee once said: "Empty your mind, be formless, shapeless, like water.
If you put water into a cup, it becomes the cup.
You put water into a bottle and it becomes the bottle.
You put it in a teapot it becomes the teapot. Now, water can flow, creep, drip or it can crash. Be water my friend."
