Muchimi and Chinkuchi
Muchimi (moo-chee-me) is an older Okinawan (Hogen) word that refers to adhering to your attacker's body. Sticking to, or riding, the attacking arms or legs is the most common understanding. When the sport oriented Karateka punches they often retract their punching hand when throwing the secondary punch. If we allow our deflecting (blocking) hand to remain in light contact, the attacker will not even know that we are following (riding) his returning arm and by the time we break contact with their arm we will have traveled most of the way to our target. In this way the attacker will not have time to become the defender.
Chinkuchi (chee-nn-koochh) The moment of impact between a body weapon and target, the overall muscle contraction, skeletal alignment, respiratory exhalation, Ki projection, mental focus, etc. happens spontaneously. This is known in older Okinawan circles as chinkuchi.
Muchimi techniques are often referred to as Nebari-te waza, or techniques that adhere to...
As a go-no-sen mentality (seizing the initiative later), when applied properly they happen in less than a blink of an eye, so it really seems like you knew what the attacker was going to do before they did it, so that you could actually trap, deflect, control, and strike in the time it takes for the attacker's initial strike to miss its target.
Both Muchimi and Chinkuchi are vital elements in what some people refer to as close quarters combat. Blocking and striking simultaneously is good. Blocking BY striking is better.
Chinkuchi is when you are up close and personal, maybe 1/2 a step, one step at the most. At times you might be standing toe to toe with an aggressor and they are as good and as fast as you are. At this time if rhythm, timing, body movement and controlling balance isn't enough then you need more speed. Speed is relative, after normal athleticism, to a point, speed of the hands is really only controlled by the mind, once the movements are ingrained in the muscle memory you just tell yourself "Faster!" and you will be fast enough. Tell yourself you're not fast enough and you won't be. Its that simple. You don't have to be faster than a speeding bullet, just faster than your attacker. He is human, you are human. As the saying goes...what one man can do, another can do.