The closed upward diagonal cut. This was probably the easiest cut for me to get right first time but I did experience some issues with it, namely a strange injury that I didn't see coming until it was too late. No, I didn't cut myself but it did put a halt to my practice for at least a couple of months and I had a constant reminder of what I'd done for a few months more. For that reason, I've decided to have a quick chat about it in the hope that some of you might benefit from my mistakes.
You all know already what cut we're talking about but just to reiterate;
The cut starts from your lower left, forcing your arms to overlap which makes it a closed cut. The sword is brought up diagonally through the cut, finshing just past your right shoulder. Nice and easy.
As long as you make sure that your edge alignment starts off correct, the way that your arms move over each other actually helps maintain that same alignment all the way through the cut. It also 'forces' the whipping action and tip acceleration that bottle cutters train into their cuts as the left arms movement becomes more restricted the further into the motion you are but the right one remains free. So from that perspective, with the guided hasuji and the forced and sudden tip acceleration at the end, this cut on its own should be a no brainer after a handful of attempts.
BUT...There is however, the risk of over extension to watch out for. Don't get me wrong, it's not a worry once you know about it. It takes a bit of explaining so bear with me.
At the end of the cut, the movement of your left arm becomes more restricted, this is what provides the whip of the tip without you even having to think about it. You left arm is no longer able to move as freely as your right. The pivotal point therefore is now your left hand, and your right hand is moving around that point. With all the momentum of the sword and the distance between your left and right hand, this means that you can actually wrench your right arm quite harshly as the weight of the sword tries to pull it further to the right than it really wants to go. As I found out, this injury is well worth avoiding. Fortunately this is easy enough.
- Keep your hands closer together. I've learnt the advantages of having a well sized and shaped tsuka. being able to have your hands closer together without there being excess below your left hand is one of those advantages. In order to wrench your arm like I've described, it needs to pivot around your left hand. if your hands are closer together then that arc is smaller and therefore there is less wrenching. :) happy times.
- Your body should be involved in this cut as well as increasing the range of movement you body makes in the cut will reduce the distance your arms have to move. Learn to twist your body in the cut. Not only does this help with the aforementioned problem, it's also a much overlooked point with cutting. Your body is so much stronger than your arms its just not funny. use your body more.
- Use correct Te no uchi and awareness to stop the cut after you've passed the target. Theres no point in cutting the air so stop the sword from moving after the target has been seperated. Hey, I'm as guilty as the next person for making my cuts too long, so I still know what Im talking about here. But the point is the shorter this particular cut, the less over extension problems and messed up muscles (sprains & strains) you're going to encounter.
Ok, so thats the heads up with this particular problem I had. Im sure most of you will be fine, but it's better to be clued up than end up injuring yourself and having to take a time out. They're no fun at all. I think something to take home from anything I myself or anyone else writes on this subject is to pay attention to your own body. These words are just a guideline and there's nothing I've ever written or said, that could ever be taken as gospel so to speak. Learn from your body's feedback, experiment and play safe.
Happy cutting :)