The concept in CMAC is to stay out of trouble whenever possible.
The best form of self-defence is not to be there in the first place. If that is not possible there is a Chinese dictum – “we beg and we plead not to fight and then we strike!” Although we also profess “karate ni sente nashi,” meaning “there is no first attack in karate,” O’Sensei Kim pointed out that it doesn’t mean you have to wait for the person to hit you. The fight started when they made their intent clear. So our first strategy is to have the correct state of mind, “ai uchi,” meaning “we are ready to die if we must and to take the assailant with us.” The assailant should perceive that this encounter is going to be a battle of life and death and we trust that we will both choose life.
Responding to the opponent's attack – a counter.
SEN – “AHEAD”
The Japanese character for “sen” can also be read as “saki.” It means “before or ahead” but in the terms “go no sen,” “sen no sen” and “sen sen no sen,” it is an abbreviation of sorts for the word “sente,” meaning initiative or lead. The “te” in sente means hand, so sente directly translates as “beforehand.” In budo, sente refers to an attack or the initiative to attack. As O’Sensei Kim puts it – beat the opponent to the punch.
GO NO SEN – “LATE ARRIVES AHEAD”
Go no sen (post-initiative) is a concept in which a combatant seizes the initiative in a fight after the opponent has already started an attack. In other words, once the opponent starts to attack, the defending combatant performs their technique. The go no sen technique can take various forms, since it depends on the use of the energy and momentum of the attacker. Go means “after.” We move in harmony with the attacker, but it is the attacker that is taking the initiative in the attack and we are mirroring his or her movements. In O’Sensei Kim’s words: “When you know how an opponent fights, you know when to move in on him, or if you're very skillful you know when he's thinking (body language) and you can move in ahead of him. Ahead not only of his action but ahead of his thought.”
Go no sen involves blocking any attack strongly and then launching a counter attack, also known as “osi waza.” In the case of a jodan oi zuki attack, the defender could shift back into zenkutsu dachi and execute a strong jodan age uke, and then deliver a gyaku zuki as a counter attack. A chudan oi zuki could be responded to by a chudan soto uke and a gyaku zuki. Again, after the counter, it is important to hold zanshin and then shift out of range and back into kamae.
Go no sen is not just a counter-attack, but also a mental state, a level of concentration assumed during combat. It is more correct to say that it is a harmonization with the very movement of attack, not just defense. Go no sen can also be seen as part of a philosophical and moral code, emphasized when one considers the term “DO” (道, dō) or “Way,” meaning that the karateka should never take the initiative in an eventual and inevitable confrontation. As stated earlier, this is also “karate ni sente nashi.”
SEN NO SEN – “AHEAD OF AHEAD” / “LEADING/INVITING THE INITIATIVE”
Sen no sen means “before the attack.” Sometimes this timing is also called “mae no sen,” mae also meaning “in front of.” Sen no sen implies that Semete is aware of Ukete’s intention of attacking and right at the time when Ukete is starting to attack, Semete steps in and stops the attack. One distinction between this and the following is that in this case Semete’s action follows Ukete’s physical movement.
“When you don't just know when he's thinking, but can dissipate his Satsui or evil intent.
Set up techniques, get him to move as you wish.
Set him up for the foot sweep.
Utilizing inviting techniques.
Utilizing feigning techniques. - If you're hurt pretend you're not and vice versa.
– O’senesi Kim
Sen sen no sen is an even more refined concept in regards to timing. The term consists of a repetition of the term “sen.” So this refers to the timing before “sen no sen.” It is the case of initiating a movement intended to lead the attacker’s spirit as well as to draw forth an actual attack, in order to utilize this attack
for a defensive technique. This is when you don't just know what and when they’re thinking, but how and when they are planning on doing it so that you can forestall their action and can dissipate their satsui (evil intent). In this case Semete’s action preceeds Ukete’s physical movement.
As an extension to sen sen no sen, there is “kake waza.” This is charging without the opponent making an attack the instant that there is “kyo” (opening).