Tenouchi in kendo means the swordsman's grip on the sword. Literally translated it means "the inside of the hand", in other words, the palm of the hand. When referring to the bogu it means the leather palm of the kote. In Japanese generally it can simply mean "skill".
There are many common mistakes people make when holding and swinging the shinai.
- Holding too tightly with the right hand.
- Opening the grip of the left hand to increase the size of the swing.
- Holding the shinai with the wrong part of the left hand
Strength at the bottom, softness at the top
I was taught that you should hold the shinai mostly tightly with the fingers at the bottom of the shinai handle, in other words the little fingers of your left hand. Then your grip should be slightly less with the thumb and index finger, a bit less with the little fingers of the right hand, and softest with the thumb and index finger of the right hand.
Eventually tenouchi becomes so quick and efficient that even though you train all the time, you no longer get callouses on your hands. This happens at around 7th dan I believe...
Holding too tightly with the right hand
People who hold the shinai too tightly with their right hand find that:
- Their cuts are not as accurate
- Their cuts are slower
- They tire more quickly
- They develop blisters on their right hand
The correct way is to hold more lightly with the right hand. You can see this by less of a bend in the wrist. The fingers appear a little more open, with the index finger reaching forward to just touch the tsuba.
Holding the shinai with the wrong part of the left hand
The first picture shows the shinai being held with the wrong part of the hand, with the tsukagashira (end of the handle) lying between the two bumps on the heel of the palm.
The second picture shows the correct way to grip the tsukagashira, with both bumps of the heel of the palm on top of the handle.
Opening the grip of the left hand to increase the size of the swing.
This is pretty self-explanatory. The top picture is the incorrect way. This is a hard thing to be aware of by yourself. Usually it takes a sensei or senior student observing you to let you know if you are doing this wrong during suburi.
Below is the correct way. In kendo, the little fingers of the left hand should never release their strong grip on the tsukagashira. This means that your wrist has to provide the flexibility and strength for the cut. Chiba sensei's technique for developing this strength and flexibility is to perform kirikaeshi with horizontal men cuts.
Tenouchi and strength
There is undoubtedly a connection between good tenouchi and strength in your hands. Next time you train with an 8th dan sensei, have a good look at their hands. You will most likely notice that they are pretty strong, with what looks like bicep muscles on each finger. This only comes from lots and lots of training.
This takes us back to the importance of suburi. Even if you don't do 1000, daily suburi will definitely make it easier to strike sharply.