I don’t really post about technique or form here, as I don’t think the written word is a very good format for that. However, I was speaking with a friend a few weeks ago about our kobudo and he mentioned the circles in our art, speaking in particular about the nunchiyaku. I paused for a second and then kept going. The term “circle” is a pretty common shorthand for a variety of shapes in most martial arts, but the comment stuck with me. That was because there are not actually any circles in our art, at least as far as I can see.
Of course there are curves- pretty much all our blocks and strikes travel in a curve of some sort- but the best way to describe those curves is probably a parabola, or an ellipse. Perhaps a J? Not a circle. Never a circle. The strike or block should have an apex. With some weapons- the bo for example- if the hands do not leave the body-box, as they not supposed to, the tip’s parabola is pretty obvious. With others, like the nunchiyaku, it can be harder to see and, more importantly, to do. This is mostly because it is tempting to move the tip of the nunchiyaku in a circle. This is easier to control, since it keeps the force in the end of the weapon constant and easily predictable, but it is incorrect. There should not be constant force in the weapon, but a tug at the end of the swing where the tip is hitting the apex of the curve and is going the fastest. This gets even harder to see, and do, with longer more flexible weapons like the sansetsukon or suruchin but again the strikes are not circles but parabola. (This is one difference between the suruchin and, say, poi- the movements are designed for striking a target, not just spinning.)
Look at it this way:
A circle travels like this:
On this path of motion the tip of the weapon stays a constant distance from the center and with a constant input the force in the direction of the velocity is constant at any point along its path.
A parabola travels like this:
The tip of the weapon is furthest from the start at the tip of the curve (the vertex), and if constant energy is applied the force changes along the path of travel, with the tip moving the fastest at the vertex.
Obviously this is hard to explain without a moving weapon, a way to relate it to the user’s body box, a target, and some attention to methods of energy development, (and more advanced, as well as more technically accurate, geometry). But even though it is difficult to describe in words it is an important distinction. The parabola is faster, develops more power (and allows for use of things like compression and expansion of the torso in power development that circles do not), and is harder to both see and predict. On the defensive side it absorbs energy a little differently and stays closer to the body-box, the only area one needs to defend.
Anyway, short comment about technique, or geometry I guess.