There are many videos showing bokken techniques on the Internet, mainly presenting techniques and forms by Morihiro Saito from Iwama.
The information I am sharing today is not readily available anywhere. It was handed down to me from my teacher, sensei Ken Williams, who was the first British dan grade and chief instructor.
The first thing is how you treat a bokken. A bokken represents a sword with a razor sharp edge, and should never be treated as merely a piece of wood. By having respect for a bokken you have a right relationship to it, which means you will learn more from it.
I have seen people touching the edge of the blade or handing it over by the blade. Generally only hold it by the handle. You can touch the back of the blade when performing certain techniques or handing over.
The blade is an extension of your body. If you practise with this in mind, your bokken technique will not only be more effective, your normal aikido practice will also become more powerful. I’ll explain that below.
When you hold the bokken, hold it lightly. You should generally be holding it just tightly enough for it not to slip. The back hand is doing most of the work, while the front hand is supporting. The back hand is right at the back of the handle, while the front hand is right at the front.
When you hold the bokken, holding it lightly, extend ki through it. What I mean is, feel like the bokken is an extension of your arms, not just a separate object you happen to be holding.
When you extend ki, the bokken will be steady. There will be a steadiness that can't easily be deflected or slapped away.
When in readiness position, imagine you are extending ki through the point of your bokken right to your adversary’s face, between their eyes. If there was someone in front of you, all they would see is the point of the blade, which is very disconcerting.
So if you hold lightly and extend ki towards them, and they tried to slap your blade away with theirs, it would be hard to move and would just bounce back.
Always keep a forward feeling when facing an adversary. Keep that forward feeling even when lifting the bokken to cut. That is why, if the blade goes too far back when lifting to strike, you will be pounced on.
In sword fighting, as in any martial situation, adversaries are looking for openings, weaknesses in your energy. Even rough breathing will give an opening, which is why it is important to breathe smoothly and quietly.
So when you lift, only lift as far as is comfortable, and you don’t feel any stretch on your front.
Now when you cut, you let the bokken drop by its own weight. You don’t try to force the bokken down. This would cause it to bounce at the bottom, upsetting your balance and making you vulnerable.
If you let the bokken drop, when you reach the bottom it will naturally stop. It is then ready to move in any direction whatsoever.
At the end of the cut, drop your hips slightly. This makes the cut very powerful, and keeps you stable yet fluid and able to move again.
Practise your cut many times, 50 or 100. But make sure every cut is straight and true, complelety relaxed, and rock steady at the bottom. It is better to do 50 cuts with full awareness of each one, than 1000 cuts just hacking mindlessly.
Some people might ask, “isn’t cutting with relaxation weak?” Have you tried to chop wood? At first you would have used all your force to chop the wood, it would have been hard, and after 15 minutes you would be exhausted.
After a few days of this, you would learn to relax, and realise it is better to let the axe do the chopping, and you just guide it; then you chop more easily, and you can go on for hours. It is the same with the sword.
By learning to hold the bokken lightly and extend ki through it, you can then do the same with another person in regular aikido practice. You will be able to move them much more easily and your throws will become much more powerful. That is the secret benefit of weapons practice.