In true budo there are 2 moments to react. One is to move at the last split second. The other is to move as you sence Ukemi's intention. All in between can be seen by the enemy and movement can be adjusted/intercepted by the enemy. A feint or tactical move is good to draw or to freeze, but this would still lead to one of the two for the outcome.
Sente
It is common that karate is accepted as a defensive art. This is partly true. Karate ni sente nashi means that one who practises karate never attacks first, mentally or physically. My personal interpretation is that this means to live in peace and try to search for this path. If somebody interferes this path, always try to avoid the conflict, never start it yourself. However, if you feel the enemies intention to be evil, you have to engage in "sente". So from that moment on you have to be in attack mode. Untill the moment you can control the situation not using your (physical) karate, it is the best. But if you don't have any other option, lead him to his own defeat.
I believe the common mistake is to wait, wait and wait for the enemy to launch the attack and then start to defend. I believe you can sence the enemy's inention. So onces the enemy enters the ma-ai and you feel you have no choice.....
However, we must all hope for peace and joy, so try to avoid all conflict.
Ashibarai, a movement that requires correct timing. Though in a large movement, I protect my seichusen and opening it to chudan level to "force" a jodan attack. It would have been more practical to also close the distance and lowering my kamae at the same time.
Go-no-sen - go sen no te
This refers to "defense, counter" However, I don't believe it to be defense, as I explained in "the body has multiple functions". One should receive the attack with the intention to put ukemi in a weak position. One should act before the opponent regained his strength and launches his
second attack. As in maegeri uke, after performing uchi harai,
gyakuzuki should be done before uke regains his balance.
In the example below, I receive the attack, but grabbing it in such a way that I'm already setting up the kote gaeshi.
Sen-no-sen - sen sen no sente
The principle
of sen-no-sen is to receive the attack and attack the opponent at the same time.
The moment the opponent attacks, avoid it and attack in the
same movement. Use otoshi, nagashi, noru, inasu and irimi - for example - to facilitate sen-no-sen. An example:
Sen-sen-no-sen - sente
A sometimes misunderstood concept is that you attack
first. Karate ni sente nashi: there is no first attack in karate.
The moment that you spot the attacker initiate his move you move too
and mostly reading his mind so well, that your attack reaches him,
(sometimes) before he even moved. In sen-no-sen
the counter was placed when the opponent finishes his attack. In sen-sen-
no-sen your counter is placed even before your opponent completes his
attack. This askes for great reaction training and mindset. You have to read his mind in order to know when your opponent
will attack. In other words, you have to sence his intention.