What size bo staff is best for me?
This is a very common question, and it is very easy to answer. Your ideal bo staff should be approximately the same size as you. If that is all you were looking for, then you can stop reading here. If you want to know WHY, then please read further!
The why, of sizing a proper size bo staff is a little more complicated, but I think anyone can understand it. After all... lets say you just read my answer above, and then say to yourself, self, how about a just use a bo staff that is a foot bigger than me?! Why not! Well... of course you can do whatever you want, but to understand why I say a proper 'self-sized' bo staff is best I need to explain some physics in terms of martial arts.
First off, just know I am a seasoned black belt, who has been making staffs for around 8 years now, and I have a degree in physics, and taught physics at all levels for 10 years. So that is who is answering this question, and I doubt that many others would have the qualifications to answer it in the way I am about to. So here we go!
To understand the way a staff works, you need to understand torque. Torque, in physics is a force that pushes on something in an off center way that makes it rotate. I say off center for a very specific reason. For instance, think of a merry-go-round at the playground. To make it spin you push it to the size and it starts to spin. There is no way to push, no matter how hard you pushed at the CENTER of the merry-go-round, to make it rotate. That is not the way torque works. Thats just a force. Torque is a force that makes something spin. You can lift your bo stall up and down and side to side, by pushing on the center, but to make it rotate, you need your hands placed off center applying a force. One hand one way, the other hand the other way to make it spin! To reiterate one hand pushes while the other pulls.
Now lets add another concept. (This is physics 101 by the way) The concept of weight. As you can imagine, if the merry-go-round is very heavy. Lets say 10 heavy construction workers are sitting on it, and you give it that same push to the side (torque) it will move, but MUCH slower. Because its hard to get all that mass (weight) moving! The staff is the same way. A heavier staff will accelerate (speed up) slower because the weight or mass of it resists the torque that you apply. A lighter staff will be easier to get swinging because it doesn't need as much force. So if you put a normal size force on it, it will swing really fast! (I'm not saying anything mind blowing hopefully, because your own experience being alive on this planet from a small size, shows us these universal laws of motion! They are inate and on some level intuitive)
By the way, this is why tapering can have such a huge effect on the performance of the staff. You aren't really removing that much weight. But you are removing the weigh at the ends, and this makes an object much easier to rotate. You reduce the weight by a quarter of the total maybe, but it will be near twice as quick and easy to make it swing.
And now the final concept needed, to explain why your staff should be your size. The final concept is the length of the staff. If you imagine our merry-go-round once again, let's say you can stand anywhere you wanted, either at the center of it, or somewhere near the edges. Where would you push to get it to move the fastest? Of course you would push it at the edge! Immagine if you pushed near the center. It would be very hard to get moving. This in physics is called, Rotational inertia. Its a fancy word that means, how much an object resists rotating. A big truck needs a HUGE engine to get it moving, because it has a lot of weight or inertia. But objects that you want to make spin have their own intertia too. Rotational inertia. You already know one of the factors that makes an object resist spinning. And that is its mass. But what is the other? Think of the carousel example we just gave! And where you would want to push it.
Thats right! If you push it toward the center, it will become almost impossible to get it to rotate. But if you push it more toward the outside, it's much easier. Does that seem to start making sense for staffs yet?
Ok, lets finally answer the question. Think of a super-duper long staff and you are holding it. Its WAY longer than you. That means that there is a LOT of mass far from your little arms. Your arms are more toward the center then with a longer staff. Therefore, when you give it a push, you have MUCH less effect on making it accelerate with any speed then you would if your hands were further out. In fact, it's not just less, it's a LOT less. Also... lets imagine someone is striking your staff at the dojo. If your staff is huge, the OTHER staff is now trying to make your staff rotate by smacking it hard at the edge. Normally your hands and muscles would resist this, but if you are holding your hands close to the center of your long staff, the impact it could rotate right out of your hands. If your staff is HUGE and they hit you at the end, there is MUCH more torque from the other staff and you have to hold on MUCH tighter, if you even can. This is because they are hitting it (force/torque) much farther from then center then a normal sized staff. In other words, your gigantic staff is more of a liability than an asset if you are swinging it, and not using it just like a spear (which is ok and makes more sense for a long staff)
On the other hand, if your staff is too small, now your hands are more toward the edges. So when you go to swing the staff the end of the staff, is moving more at the speed of your hands, and you don't get that snap you want. The ends, being closer to you never really get up to speed. Think about the merry-go-round one last time. Its moving faster at the edges then the center.
So with a bo staff, there is a sweet spot where the staff accelerates just right, has the perfect reach, and has enough control to take and give hits without being unstable. And that is when its at your own body height.
No matter if you are small or large, to develop proper technique, trust your body, let the staff fit to your size and let your body develop your best technique.
Leave a comment