The following are some of the principles that Bruce Lee distlilled and incorporated into Jeet Kune Do. He felt these were universal combat truths that were self -evident and would lead to combat success if followed. The “3 Combat Ranges” in particular are what he felt were instrumental in becoming a “total” martial artist. This is also the principle most related to mixed martial arts.

 The Three Fundamental Principles of JKD

Jeet Kune Do techniques should contain the following properties/prinicples:

•    Efficiency – An attack that reaches its mark

•    Directness – Doing what comes naturally in a learned way.

•    Simplicity – Thinking in an uncomplicated manner; without thought.

In addition the following are considered underlying JKD principles; 

I. Be like water – (flow/fluidity in movement) 

JKD students reject traditional systems of training, fighting styles and the Confucian pedagogy used in traditional kung fu schools. JKD is  a dynamic concept that is forever changing. 

JKD students are encouraged to study and analyze every form of combat possible in order to understand the principles and apply what works for the individual.

Flow is a critical attribute of JKD technique. It is difficult to define and even more difficult to learn. It is both mental and physical in nature. 

II. Economy of motion

JKD students waste no time or movement. When it comes to combat JKD practitioners believe the simplest things work best.

A. Stop hits & stop kicks – (longest weapon to the nearest target)

This means intercepting an opponent’s attack with an attack of your own instead of a simple block. JKD practitioners believe that this is the most difficult defensive skill to develop. This strategy is not a typical feature of most traditional Chinese martial arts.

B. Simultaneous parrying & punching (JEET) - Intercept

When confronting an incoming attack; the attack is parried or deflected and a counter attack is delivered at the same time. Not as advanced as a stop hit but more effective than blocking and counter attacking in sequence.

C. No high kicks

JKD practitioners believe they should restrict their kicks to their opponent’s shins, knees, thighs, and mid section. These targets are the closest to the foot and provide more stability.

D. Non telegraphic

A punch/technique should be felt before seen

III. Learn the 3 ranges of combat * (and the technique most appropriate for each range)

•    short

•    medium

•    long

Jeet Kune Do students train in each of these ranges equally. According to Lee, this range of training serves to differentiate JKD from other martial arts. Lee stated that most but not all traditional martial systems specialize in training at one or two ranges. Bruce Lee’s theories have been especially influential and substantiated in the field of mixed martial arts, as the MMA Phases of Combat are essentially the same concept as the JKD combat ranges.

* Bruce Lee also considered "grappling" as a potential "range" (perhaps a 4th range or a likely subset of the short range in the reality of combat ?)

IV. Five Ways Of Attack

A. Single Angular Attack and its converse Single Direct Attack.

B. Hand Immobilization Attack and its counterpart Foot Immobilization attack, which make use of “trapping” to limit the opponent to function with that appendage.

C. Progressive Indirect Attack. Attacking one part of the opponent’s body followed by attacking another part as a means of creating an opening.

D. Attack By Combinations. This is using multiple rapid attacks as a means of using volume of attack to overcoming the opponent.

E. Attack By Drawing. This is creating an opening with positioning as a means of counter attacking.