As an experienced Iaido trainer, I get a lot of students in my class who come into the program with katana swords that are not right for them. Since Iaido is the art of drawing the katana from the sheath (saya), striking, and then returning the sword to the saya, all in one fluid and controlled motion, the length of the blade is important.
I’ll even admit that my first katana was too big for me, leading to an accidental cut on my left hand. Fortunately, nothing too serious, but it changed my perspective from having a katana that looks good to one that actually fits the intended purpose for the training I was signed up for.
When working with a 26″+ sharp blade, safety is my primary focus, therefore I have changed my registration process to inform incoming students of sizing calculations before class begins.
How does having a sword that is too long affect safety?
Not having the katana of the proper length can cause difficulties in controlling the thrusts of the blade, as well as false depth perceptions. What I mean by ‘false depth perception’ is that if the blade is too long, it’s easy to underestimate the range it will have during training. If the actual length of the blade reaches further than you think it will, you can easily injure yourself or others training with you.
How to size the sheet
There are numerous methods of sizing, and depending on the sensei you speak with, each may suggest a different sizing method. There are two considerations to keep in mind when sizing a katana; the length of the handle (tsuka) and the length of the blade.
one.) To size the tsuka, place your arm at your side with your forearm forward so your elbow forms a 90-degree angle. Now use a tape measure to measure the length from the elbow to the base of the wrist. This is roughly the length your tsuka should be. If your tsuka is too long, it can interfere with your movement and get caught on your side, causing the blade to slip.
two.) To measure leaf length, the method I’ve found works best and suggest my students follow is a leaf height-to-length relationship chart (one can be seen below in the resources section). ). If you are 5′ 2″ tall, your blade length should be 27.5″ and for every 2″ of height add a half inch to the blade length.
If you’re still not sure what length to get, you can always start Iaido training with a Bokken, a wooden training sword. In fact, I recommend this as it allows you to get acquainted with the art without risking harm to yourself or those around you.
Now keep in mind that these sizing methods are simply my method of sizing my students and you should consult your sensei on the proper length before purchasing a katana.
Iaido is a beautiful martial art and the katana is a great weapon that comes from ancient Japanese tradition. I advise all readers to use their good judgment and use a katana at their own risk.
