Japanese Sword Arts FAQ Version 2.7
10. What sort of weapons are used for practice?
The usual weapon used in Kendo is the shinai. It is constructed of 4 pieces of split bamboo. The tip of the shinai is covered in leather; the four staves are held apart by a t-shaped piece of rubber. The staves are held together at the opposite end by a long leather handle. The handle is round rather than oval like a real katana. A leather lace tied in a complicated knot about a third of the way from the tip keeps the staves from spreading too far apart. A string runs down one stave -it signifies the dull edge, or back of the sword.
The split construction allows the staves to both flex and compress against each other, absorbing much of the energy of the blow. Attacks which miss the armour cause bruises; nothing more. Poorly maintained shinai can be dangerous - bamboo shinai must be checked and sanded regularly to avoid splinters, and oiled or waxed to help prevent drying out and subsequent breakage. For this reason carbon fibre shinai have become popular. Although expensive and less lively-feeling compared to bamboo, they are virtually maintenance free and last for years. Also, carbon fibre shinai may be purchased with an oval grip, which many people prefer. Previously, only expensive hand-made bamboo shinai had oval grips.
More advanced kendoka use bokken, or wooden swords. Bokken are usually constructed of white Japanese oak, although they can be made of a variety of exotic hardwoods. They are curved and sized like a katana, and the handle is about the same length and oval. Kenjutsu is often practiced with bokken, and in fact kendoka use bokken to practice the kendo kata, which are derived from kenjutsu.
Iaidoka at lower ranks use iaito, which are dull katana. A good iaito at the least has a proper handle with rayskin and cord grip and is constructed strongly enough so as not to be a danger in practice. The more expensive a iaito gets, the more closely it's construction mirrors that of a good sharp sword (shinken).
Kendo kata swords are like iaito, but a little heavier and capable of withstanding the blows received in the course of the kata. Kenjutsu is sometimes practiced with these.
Sharp katana, or shinken, are real Japanese swords. Iaidoka in the ZNKR are required to take their 5th dan exam using a shinken; advanced kenjutsu practice uses them.
10a. What is required for shinai maintenance?
Shinai are not ready for use when brand new. They must be taken apart, sanded and oiled to make them safe for use in practice. Additionally, staves which are splintered or damaged from use should be repaired or replaced. Here's some instructions for doing so:
Untie the string (or tsuru) at the handle and pull the tsukagawa (leather handle) off. Hold the staves together with one hand while you do this, and before you separate them mark the butt ends so you know which is top, bottom, left, right. Then pull off the sakigawa (leather tip) and nakayui (the fancy knot in the middle) along with the tsuru.
NOTE: there's usually no need to untie any knots other than the one at the handle - make sure you undo the string there, not the leather! However, from time to time, as the nakayui works loose it should be retied as one of its functions is to retain large splinters within the shinai body rather than to allow them to protrude.
The sakigawa, nakayui and string all slip off the end together. There's a rubber t-shaped thing called the sakigomi that seperates the staves at the tip, it may come off with the sakigawa or you may have to pull it out. Inside the handle portion of the bamboo, there's a little metal square that fits into some notches. Don't lose it, it helps keep the staves in the proper position relative to each other.
Once you've got it all apart, take some sanding paper and smooth over the edges of the staves where they meet and rub against each other. You'll note that they are fairly sharp when new. You don't have to do a lot of sanding - 2 or 3 strokes should do it. The purpose is to make the staves move smoothly past one another without binding or generating splinters. I like to use a foam sanding block for this job, but anything with a medium-fine grit should work. You can also get special tools from Japan, I have a combination file/plane that works very nicely.
Once that's done, lay the staves down on some paper towels in your basement or something (somewhere that spilled oil won't matter) and oil them. I like to lay them outside down, so that the concave inner surface is up. Then I fill the concave surface with oil. A light oil is best, like sewing machine oil or gun oil (without blueing), but you can use vegetable oil like Mazola. There's also commercial oils available from Japan. Anyways, if you use a light oil let the staves soak for at least 5 days, if you use vegetable oil let them soak for 3 days. Oversoaking with the light oil isn't a problem, but too long with the vegetable oil can leave them heavy and soggy. Check each day and if the oil has been absorbed add a little more. When they're done soaking, wipe off the excess oil and reassemble.
A faster alternative is to hand rub the oil into the take... be careful that there are absolutely no splinters if you chose to do this... there shouldn't be anyway. Take a cloth lightly soaked in oil and rub the take on all sides to help them absorb the oil.
Check your shinai for cracks and splinters before, after and during each class. Small splinters can be sanded out. Follow the same procedure for disassembling and reassembling your shinai.
Cracks and larger splinters should not be repaired. Save the take from shinai that have been damaged. By carefully selecting from among them, you can rescue a damaged shinai by substituting the spare take which fits best. Repaired take have been known to cause serious injury.
If you are at the stage of your practice when you are hitting a real target (another shinai or a motodachi in bogu) then you should have two shinai in case one breaks during class.
In addition, to distribute the wear over all of the take as evenly as possible, from time to time 'rotate' the take (unless you have one of those fancy dobari kobun tsuka's [the ones with the oval cross section]). To rotate the take, undo the tsuru knot where it ties to the tsukagawa. Slide the nakayui slighltly upwards (towards the sakigawa). Rotate the sakigawa and nakayui 1/4 turn to the right (left if you prefer just go the same direction each time), pull the tsukagawa partway off to loosen it and rotate it 1/4 turn in the same direction. Reseat the nakayui and tsukagawa and retie the knot.
The purpose of all this is for safety and durability. Shinai come from a climate which is much more humid than North America or many parts of Europe, and so it is necessary to oil them to prevent breakage and splintering. Unoiled shinais will tend to splinter more, break sooner and thus be more dangerous and cost you more money. Properly maintained, a bamboo shinai can last as long as a year.
10b. What are the regulation sizes for shinai?
| Itto shinai standards: | |||||
|---|---|---|---|---|---|
| Age | Max Length (cm) | Min Weight (g) | |||
| Men | Women | ||||
| <= 15 | 114 | 425 | 400 | ||
| 16 - 18 | 117 | 470 | 410 | ||
| >= 19 | 120 | 500 | 420 | ||
| Nito shinai standards: | |||||
| Shinai | Max Length (cm) | Min Weight (g) | Max Weight (g) | ||
| Men | Women | Men | Women | ||
| Daito | 114 | 425 | 425 | ||
| Shoto | 62 | 280 | 250 | 300 | 280 |