To me the potential uses for any kata gesture approaches the infinite. More than most can process, and certainly a long lifetime study to begin to appreciate.
I understand this is difficult to pass to the beginner or even the dan. Leaving one wishing for a simpler answer.
But let us try to take the first step towards the infinite.
I am just going to suggest one application potential to the second series of movements from the Isshinryu kata Seisan. Which is where Isshinryu begins after all.
Just one out of many potential applications for that set of movements.
The second set of movements from Seisan kata.
1. Starting from left foot forward Seisan stance. Against at attacker stepping forward with their right foot and attempting to grab you with their right hand.
a. The right foot moves forward with a right crescent step forward into right Seisan Stance.
b. As your right foot circles into your left foot, your right hand which is forward, clenches the fist and draws it back to your right chamber on your hip
c. At the conclusion of the stepping motion, your left hand strikes out from left chamber.
The second set of movements from Seisan kata.
2. Starting from left foot forward Seisan stance. Against at attacker stepping forward with their right foot and attempting to grab you with their right hand.
a. The right foot moves forward with a right crescent step forward into right Seisan Stance. While this crescent step moves forward, the right foot circles past the attackers right foot. As this occurs the lower right leg brushes past their lead let moving it at the knee. This results in their lead leg buckling to the outside of your step. Their center begins to fall.
b. As your right foot circles into your left foot, your right hand which is forward, clenches the fist and draws it back to your right chamber on your hip. You take your right hand and open the hand, then grab whatever in convenient: as their clothing or their right upper arm. Then retract the grasping hand further drawing them forward. Pulling them down over their collapsing center.
c. At the conclusion of the stepping motion, your left hand strikes out from left chamber. The left fist strikes at the end of the stepping into the target of opportunity. Ie: the side of their rib cage, into their armpit, into their arm, into their face.
Even a simple example becomes filled with other options.
Be honest with yourself, If you do this kata, how frequently do you perform this movement against an attacker to demolish their attack, And that is what is needed, the reason d’etre of the movement. Of course there is much more involved.
I have just described the physical movement of the kata section. And a mental application of that section against an attack. Or one application of those movements. But knowing that Application Potential for that kata section exists is far from the whole picture,
And understanding as Application Potential is only the small part of the story.
The real work is working on that Application Potential until you can make it work every time, against any attack. A much larger set of principles than you began this analysis working with.
That there are three components behind any karate movement is often forgotten. Hard training is often pushed and of the three “Spirit” is IMO the least mentioned.
But it is the most critical for it is the Spirit behind the movement that allows you to move from Application Potential to Application Realization. And that is what the true goal is.
For any application improperly applied will not work. You have to find a way to make it work every time.
A short story:
One day as I was teaching the adult group (the members averaged over 15 years on the kata we were working on) suddenly I saw the application of that movement in a new light.
I showed everyone in the group what I saw. Making it work the first time.
Then I slowed down what I was doing, repeating that application, and even in slow motion making it work. I went trough what I was doing 10 times. Then I turned to them and asked them to do it.
Time after time everyone was unable to do what I had showed, and each time they did something else which they personally felt more comfortable with. They were not newbies. But they were unable to do what I had showed them in detail.
As I corrected what each of them did, it came to me what the difference was.
It was not physical, for they all had done the kata for a long time.
It was not mental, for they all understood what I had showed.
But when the pressure of an attack (even a slow motion one) was experienced, their skill automatically shifted to something else, something they were more sure of.
If the situation was true self defense, they would be congratulated for making what they did work. However that was not the situation, they were trying to use what I had shown them.
I thought about it a moment and the difference came to me.
I have a deeper faith in every movement of the kata I teach. I trust those movements. Having that trust I made that Application Potential a Realization for me.
It takes work to forge any Application Potential into Application Realization.
The SPIRIT behind our Art is the true key.
Of course Karate is the Physical, the Mental and the Spirit.
They are bound together. That is the key behind everything.