Jeet Kune Do Theories:

Five Ways of Attack in Jun Fan JKD
Attack on intention-when they are thinking about it
Attack on preparation- when they telegraph their intentions
Attack on delivery- intercepts the attack on the half beat with a stop hit
Attack on completion- intercepting it full extension
Attack on recovery- when they are recovering; response hitting

JKD`s Five Ways of Attack

SDA (Single Direct Attack)
A direct attack is composed of a single movement. The objective is to go to the target by the most direct route. Although it is the simplest of the attacks, it is the hardest to complete successfully because the speed and timing. as well as the penetration of the opponent's defense must all he perfect. A single direct attack is made into the line of engagement or into the opposite line by simply beating the opponent to the punch, or by catching him in a moment of vulnerability. When executing a single direct attack, you lunge to hit the opponent before he can parry, without any attempt to disguise the direction of the attack. Here, you would most likely use your longest weapon to the closest target. When striking with the lead hand, it is advisable to constantly vary the position of your head for added protection against your opponent's counter. Keep the lead hand moving, as it not only keeps your opponent on the edge, but also can be delivered faster from motion than from a stationary position. Also, to minimize counters from the opponent, you should at times feint before leading.
However, do not overdo the feinting or headwork. Remember simplicity. Such an attack can also be thrown at an unexpected angle, sometimes preceded by a feint. This is called a Single Angular Attack (SAA). It is done by positioning your body in relation to the opponent so that an opening results. The judgment of distance must be good. Sidestepping or some kind of lateral movement is often used in this attack.

ABC (Attack By Combination)
ABC is a series of thrusts that follow each other naturally and arc generally thrown to more than one line. ABC is generally composed of set-ups to maneuver the opponent into such a position or create such an opening that the final blow of the series will find a vulnerable spot. You want to make sure that our attacks are aggressive enough to get your opponent to back away, otherwise he may smother your attack combinations.

HIA (Hand Immobilization Attack)
HIA applies an immobilizing technique (trap) on the opponent's hand or leg, or head (by grabbing the hair) as you crash the line of engagement. Immobilization attacks can best he set up by using any of the other four ways of attack, and traps can be performed in combination or singularly. You use this when there is a barrier, such as the opponent's arm, that prevents your weapon from scoring, or when you want the added protection of covering a threatening weapon such as a nearby fist when slipping or countering. Trapping keeps the opponent from moving that part of his body, offering you a safety zone from which to strike. It can also be used to force an opening: upon finding your opponent covered, you v would attack his hand with sufficient force and vigor to turn it aside and make an opening for your hand on the lunge Deflecting or trapping the hand while stepping forward, also limits the possibility of a successful jam from the opponent. Obstructing the leg as a preliminary step is likewise very effective.

PIA (Progressive Indirect Attack)
A PIA begins with a feint or an uncommitted thrust designed to misdirect the opponent's reactions in order to open a line for the real attack which follows instantly. The principal use of the PIA is to overcome an opponent whose defense is strong enough and fast enough to deal with HIA and SDA. It is also used to offer variation to one's pattern of attack. The distance has to be closed up a good half by the feint. The feint should induce the opponent to think you are going to h it him in a particular line;so it must he long enough to provoke a reaction. When the opponent moves his hands or arm to cover that line, another line will open and the real thrust strikes there. The succession of feint and real attack in PIA is executed in a single, forward motion. In this, it is distinctly unlike a SDA preceded by a feint, which would he two separate movements.

ABD (Attack By Drawing)
This is a counterattack initiated by luring an opponent into committing to a move. You must induce the opponent to step forward in tempo into the "within distance" area, for instance, by leaving an apparent opening. Then you time his attack, and nail him while he is stepping forward, or merely shifting his weight forward, or when he shows any sign of heaviness, mentally or physically. The success of this attack largely depends on concealing your real intentions. Or you could execute movements that he may try to time and counter in some manner such as a jam which you can predict with some moderate certainty. His commitment will not allow him to change his position or guard swiftly enough to deal successfully with your offense after his technique is parried.

Centerline Theory

In Jeet Kune Do, there are many imaginary lines that a fighter should be aware of. The most commonly used tactic is a Straight Line, this being for defense or offense .
The reason why the straight line is favored in JKD is because it is the shortest distance between two points and you reach your opponent much faster. The Basic Line or straight line is the most common line.

Wherever you look, that should be your target, allowing you to reach your opponent faster and with more power. By being in a JKD By-Jong (fighting stance) or front lead, this allows you to be one step further and closer to the target. By being an orthodox fighter, the attacks will come from the rear, which might be a straight line, but not always the shortest line between A and B. Using the shortest distance will also be non-telegraphic and this will offer you the advantage of the inside center line.

You will be able to hit him by blocking his attack, but he cannot hit you because you have the advantage of his inside centerline, which is the line between the Blocking Line and the Center Line. By taking the inside centerline, this will give a big target area on which you can strike your opponent and cause much more damage. Meanwhile, all of your vital organs are on the centerline, which is a good reason that your rear hand should always protect your centerline. Another line called the Mother Line goes from the top of your head, passing through your body, down to the floor.

It's the core axis of rotation. It is in you. The Mother Line is the attack line. It's the target area; you take advantage of it while executing the techniques. Next is the Self Center Line. This is a vertical line painted down the center of your face to your feet, dividing your body into two equal parts.

The Self Center Line moves with you, no matter what angle you turn. It is painted down the middle. When you move, it moves. This is the line you follow during practice when no opponent is present and it is mainly used to help you execute techniques correctly. All blocks and attacks should be in reference to the Self Center Line. You are protecting your Self Centerline, while trying to target your opponent's Line.

A Center Line Plane allows the core of your Mother Line to be connected with the core of your opponent's Mother Line, no matter which way either opponent moves, shifts or circles. The Center Line Plane always connects the two fighters. The outside curve line is called a Blocking Line. This line goes from the outside from any blocking motion and connects to the Center Line. A Jeet Kune Do fighter or practitioner takes advantage of the area inside the Center Line.

The Power Of Interception
Jeet Kune Do, as most of us know, translates as 'The Way of the Intercepting Fist'. It seemed appropriate to provide an article about interception itself.

The interception of an attack can be a very useful tool. It can add power to your attack without additional effort. It may require little preparation, giving the element of surprise. It also, can be extremely frustrating to your rival, helping to win the bout psychologically as well as physically.
There are many different types of interception. An interception does not have to be executed only with the fist.

You can intercept a punch with a kick, a kick with a punch, or a kick with a kick etc. Some do not even involve a strike from both sides. You can cut off an attack by simply moving into a position that will jam them, leaving no opportunity for them to land the attack. Alternatively, if he were to simply step one way or the other, you could intercept their motion with a blow, causing him to walk into it.

There are also different times during the adversaries' attack in which an interception may take place. It can occur before, during, or after their attack or movement. Before, or while the opponent is in preparation, you can read their intentions and strike before they can initiate. During their movement, there may be several opportunities to intercept.

You could strike from the materialization of their movement all the way up to their full commitment. After, or upon completion, the interception takes place as they recover and before they can launch another attack.
In order to utilize interception as a tactic, it is necessary to train certain attributes. First are your Single Direct Attacks (or S.D.A.'s), for obvious reasons. The faster, more precise, and more powerful your technique, the better chance you will have in pulling it off. Next, and equally important, is mental awareness. Your mind must be sharp in order to pick up on their movement and react accordingly.

Additionally, work to control your emotions is needed so that fear, self-doubt, and you ego do not cloud your senses and hinder your performance.

Two other attributes that need specific attention are timing and distance. Surely, they are both important anyway, but without them, interception becomes impossible. Proper timing can be responsible for some of the most devastating attacks. You can use the momentum from your movement combined with theirs, timing it so that they collide head on into your strike. While the correct distance enables you to strike the target cleanly allowing for more power and penetration.

Here are some examples of interceptions:
1. -The opponent begins to throw a front kick from the rear leg.
-You intercept his kick with a sidekick to the attacking leg as it approaches your position. This is commonly called a stop kick or Jeet Tek in JKD. Depending on your distance and timing, you can attack just about any part of their leg, from the thigh down to the top of their foot.

2. -The opponent throws a jab at your head.
-Drop and Step forward to the outside of their lead leg letting his jab pass over your shoulder. As it does, strike to their open rib cage. This is also called a slip.

3. - The opponent begins to step to his left.
- Throw a hook with your right hand, timing it so that they walk into the punch. Strike them before they complete the step, they will take a much greater impact if their feet have not yet settled on the ground.
Intercepting is almost an art in itself. It takes a lot of practice to perfect but is well worth the effort in the end. Once you are able to utilize interceptions effectively, you will gain a new level of control in both, sparring sessions, or on the street. Interception is a tool for the superior fighter. 

Jun Fan JKD Sectoring Concepts

Sectoring concepts develops the center lines or your defense and offensive concepts of moving into punching range for follow-ups.

This is the break down of some of the concepts: for a single punch

1. A Spilt sector; Parry outside of the arm and strike inside to the head or body

2. Inside parry and hit sector; inside arms attacking center line head or body

3. Outside parry and hit sector; hitting over the arm to the head or body with the same
hand.

4. Pak Sao and hit sector; slap block with rear hand and hit with lead hand

5. Cutting sector; cut off attacking angle of the punch, using your punch to counter and strike at the same time, coming from a slightly different angle.

6. Guild and hit sector; Intercepting early to guide the attack into a different angle.

7. Inside Pak Sao sector; Slap block with lead hand and counter with the rear hand

8. Cup Sao sector; Circling attacking angle or punch out and away from you by moving the center line or the body off line.

9. Lop Sao sector; Grab or grabbing control of the attacking hand.

10. Intercepting or stop hitting; you stop the attack at it's fulcrum or leverage points

You must develop sectoring principles into basic follow-ups, which are Head butts, Knees, Elbows, Kicking concepts if they evade out of your punching range, Throwing tactics, Joint locking tactics, Develop counter takedown tactics, grappling/counter grappling.

When working inside center line, (between their arms) sometimes instead of striking develop monitoring or checking the attackers opposite hand or follow-up with a straight blast (which is a number of punches up their center line)

Next Phase you want to develop sectoring combinations using the basic 1-2 combination or Jab and Cross from boxing.

Next Phase work on developing the tactics from sectoring countering sectoring.

The essence of physical fitness, the spring board from which all novices must move to a state of readiness to study the martial arts, is perfection of breathing.

Understanding the philosophy of Jeet Kune Do

1) Absorb What Is Useful

2) Reject What Is Useless
3) Add What Is Specifically Your Own

4) Man, the Creating Individual

1. Absorb what is useful:
"The idea of absorbing what is useful does not mean choosing, collecting, compiling, accumulating or assembling techniques from different styles of martial arts thinking to yourself, "I'll take the best from all the styles and put it together to form a new style." To do this is to miss the point. We are not saying "collect what you like" or, put together the best," but "ABSORB" what is "USEFUL". It is an individual investigation. To "ABSORB" means to "get into" the technique, training method and art you are interested in until you develop a "feel" for it. Until you experience "being" in it and "becoming" it you don't really understand it. For example, looking at the Malaysian art of Bersilat, trying out a few of their techniques, then saying to your self, "I like their elbow technique, I think I'll add it to my style" is a step that is self-delusional. To understand those techniques you need to go into the Malaysian art and train like they do, feel it, experience it for awhile, both in the doing and the receiving, until you've got a grasp on it. You must become a Bersilat man in order to truly understand Bersilat techniques, attitudes, training methods, etc... Once you have "absorbed "; that experience and knowledge gained is yours, not just something you've parroted from another style. Only now can you start throwing away what doesn't suit you personally, so you can reject what is useless.

2. Reject what is useless:
How do we know what is useless? What we think we see is sometimes not what we really see. For example, a karate man, kick boxer, kung fu man and Savate man were watching for the first time, a Thai Boxer throw a roundhouse kick against a heavy bag. They might immediately dismiss the idea that the kick had anything to offer them because they already feel they know that kick, but do they? If they investigated further, they might be in for a rude awakening. Anyone who has spent some time training in Muay Thai would realize that although it may look like the same kick, it is in fact not the same and it takes a great deal of training to perfect and maintain it. Not being able to perform a technique successfully is another reason for rejecting what you think is useful when it might not be. We should question ourselves. Why does that technique from that style work for them? Why doesn't it work sometimes? The important thing about rejecting what is useless is that you don't reject anything until you know why you are rejecting it! You could be throwing away a real jewel because of your own lack of understanding. Possibly your timing or distance is off; or your coordination needs improvement. Would you reject batting in baseball just because the times you tried it you struck out? Most of the time it's your own fault that the technique doesn't work, so before you reject anything make sure you've investigated why it doesn't work for you.

3. Add what is specifically your own.
To "add what is specifically your own" doesn't mean to add anything for the sake of being different or to make ourselves or style unique and different from everyone else. It is understanding the principle at the core that really counts. By knowing ourselves and understanding the root motions we can then modify to our personal preferences. For example, how many of us still drive the way we were taught in driving school? It is because of our experience in driving that we can add our personal modifications or cheat (as the case may be); like driving with one hand while operating the radio buttons with the other, or turning the wheel by palming it instead of using both hands in the accepted driving school manner! How do we know ourselves? We must experience a great deal before we can decide what our personal preferences are in technique. We must look at martial arts with eyes that can see what is functional from the perspective of combative structure. Economy of motion, simplicity, and directness are some indicators here. To be able to discern what is functional requires understanding the principle in practical application-action. Sparring helps in this regard and no wonder Lee referred to it as the "lifeblood" of JKD.

4. Man, the creating individual:
Man, the creating individual is more important than any established style or system. Does this mean you should create your own style? In order to understand this we must distinguish between style and "personal style" All boxers basically use the same methods and "style" but the personal style of Ali is quite different from Frazier. European boxers have a different movement look than American boxers. When we are creating our own style it is an investigation into what is the best way to get more power, more speed, and more efficiency for ourselves as individuals. Who created style, then? An individual or group did. So what becomes more important, the style or the individual? This last statement in this saying is about freedom, the freedom not to be bound by any method, style or philosophy that limits our personal growth outside of that entity. The key to all this boils down to the common denominator called experience. The JKD man actively seeks experience because only by experiencing can he arrive at any sort of self-knowledge, self-understanding, or self- realization. It is good to seek knowledge of techniques and training methods, but if you stop here then you become just a collector creating a mosaic of techniques and methods that do not function or fit together in a fighting structure. Knowledge of itself has no understanding. Understanding comes from individual experience with that knowledge.

I think Trevarian best sums it up by saying, "Do not fall into the error of the artisan who boasts of 20 years in experience in his craft while in fact he has had only one year of experience...20 times."