Short History and Description

Shinai, the bamboo sword, sometimes referred as being the symbol of kendo, has been part of every kendoka's equipment for a long time. The well-known shape today has been achieved over a few hundreds years of evolution. In the peaceful period of Edo many sword fighting schools appeared, and studied the art and technique of using this weapon. Using wooden sword (bokuto) instead of the real sword has greatly improved the safety of the practices but only after the shinai was invented the free practice has truly been possible. The first shinai has been made and used by Naganuma Shirozaemon-Kunisato from the Jiki-shinkage-ryu. In Shotoku period (1711-1715) Naganuma developed the so called Fukuro shinai (translated by "bamboo sword in bag"), and established the methods of using it. Fukuro shinai is made of a tube of bamboo cut into several strips on the "cutting" part of the shinai completely covered in leather, leaving the handler intact and uncovered.

In the second part of the Edo period, at the beginning of the XIX-th century, a new form was developed, very similar to the one used nowdays. This model, called the yotsuwari shinai, is made of four bamboo strips and had a few advantages over the fukuro shinai, being more elastic and resistant. In a short time it replaces the older types of shinai. The fukuro shinai is still used today only by a small number of kendoka in some traditional schools.

The structure of shinai is largely similar to the Japanese sword. It is made of 4 bamboo strips, and it's roundly shaped with some additional fittings. It has mainly three structural parts: the blade, the handle, and the guard. The blade (jin-bu) is round shaped with a variable section, made of bear bamboo strips. The tip is called kensen or kissaki. Even if it doesn't resemble to a "proper" blade, there is still defined the edge (ha), and the back of the sword (mune). The upper part, approximately one third of the blade, used for executing the correct cutting techniques, is the so called mono uchi (as for nihonto or bokuto) or, in the case of shinai, also known as datotsu-bu. The handle is also round / cylindrical shaped, and it's made of the extensions of the four bamboo strips that make the blade. The bottom end is called tsuka-gashira. The guard is called tsuba and it's firmly fixed between the blade and handle.

The pieces that make up the shinai are well defined in number, shape and material. The most important are the 4 bamboo strips (take) which are held together by tsuka gawa, sakigawa and nakayui tsuru. The mushroom shaped element, which ensures the propper position of the bamboo stipes with a shape of a mushroom (saki gomu) is made of rubber or plastic, and is placed inside of the tip (on the top) of the shinai. On top there is a leather part that covers the tip of the shinai (saki gawa) which is firmly tied up by a string called tsuru. On the tsuru, there is placed a leather strip (nakayui) which should correctly delimit the datotsu-bu from the rest of the blade. To correctly tie the string, a loop is made close to the handle; in many cases this loop is made of small leather piece, the so called komono.

The handle is entirely covered by a leather sheath, tsuka gawa, made of dear or syntetic leather. One end of tsuka gashira is closed, at the other end the leather is doubled and strengthened. It has a leather loop formed at the 2 ends, to which the tsuru is attached. Inside the handle all 4 strips are partially cut, close (2-3cm) to tsuka gashira; here is set a metal plate (chigiri) which assures the immobility of the stripes during the usage of the shinai. The guard of the shinai is made of 2 parts: the tsuba itself and tsuba dome which fixes the tsuba to the shinai.

There are several types of shinai available, but these can be classified generally in two main categories: standard and specialized.

The standard shinai are those that can be used for trainings, competitions or exams, and meet the regulations from the Kendo Regulations (Part 1 / Article 3/ 2006.12.07). Furthermore, the standard shinai can be devised into several categories based on different parameters. One of these parameters is the length; the length varies by age and sex. Generally is used the long shinai with a length of 32-39 sun. The table below presents the standard sizes:

Age	Length	Weight* (♂)	Weight* (♀)	Name
Under 12 years old	≤111 cm	—	—	saburoku, 三六 3 shaku 6 sun (36)
12-15 years old	≤114 cm	≥425 g	≥400 g	san-nana 三七 3 shaku 7 sun (37)
15-18 years old	≤117 cm	≥470 g	≥410 g	san-hachi 三八 3 shaku 8 sun (38)
Over 18 years old	≤120 cm	≥510 g	≥420 g	san-ku, 三九 3 shaku 9 sun (39)

A second type of shinai, length-wise, is the short sword: shoto. This is used for the practice of "nitto", the technique with 2 swords/shinai. The table below presents the standard sizes for this case:

Nito	Length	Weight* (♂)	Weight* (♀)
Daito	≤114 cm	≥425 g	≥400 g
Shoto	≤62 cm	280-300 g	250-280 g

* the weight must be measured without tsuba/tsubadome

Other categories of shinai can be made by the material used to make the strips. Traditionally this is bamboo and there are several types that can be used; such as the Chinese/Taiwanese bamboo (keichiku) – lower quality, fewer fibers – or Japanese bamboo (mandake) – better quality, denser fibers. Sometimes the bamboo is treated: smoked or soaked in oil to get better performance and/or nicer aspect.

Recent innovations made possible the replacement of bamboo with synthetic material with similar mechanical properties but with a much better durability. Currently, there is only one type of material approved by ZNKR/FIK as a replacement for bamboo: composite polymer, the only producer being Hasegawa.

The shape and the profile of the "cutting" part determine the center of weight of the shinai. This is yet another parameter for splitting the shinai into several categories. In general, the shinai have a standard form, with a thicker part, just above the tsuba (jissen gata). If this part is prominently thicker, and the blade get thinner towards the top, then it is described as dobari style; the main advantage is the lower center of weight (closer to the handle) and thus easier to manuver. The other extreme, when the blade is almost the same shape (straight) throughout the entire length is known as koto/chokuto; with reference to the older swords which were straight. In this case, the center of weight is much closer to the tip.

The section of the handle is round; at least in the most cases. Rarer are the shinai with an oval handle (koban); they have been developed so they resemble more with a real sword. The length of the oval part varies from just enough for the left hand (K1 model) to the whole handle (K2 model). Generally, the oval handle helps getting cuts with better hasuji. However, this model is not so much spread, probably due to higher costs and more difficult maintenance.

Pieces of the Shinai

The guard (tsuba), according to the regulations, must be made of leather or similar synthetic material. The shape and size is well defined; it must be round with no more than 9 cm in diameter. Traditionally it's made out of thick cow leather (4-7 mm) with or without decorations. The leather must be treated so that it remains flexible or it can be used raw leather which is more rigid. Rarely it can be used lacquered shark skin; these are rather expensive but really nice. Nowadays it's very common to use plastic tsuba; it can be made in any color, there are some even transparent or decorated.

To mount the tsuba on the handle it is widely used a flexible ring, the so called tsuba-dome, usually made of rubber. The simplest model resembles a lens with a circle hole in the middle; the more sophisticated models have a special profile which assures a better montage. More recently the so called fudo-dome has been available on the market; it's made of tough rubber strengthened at the outer edge, and it's probably the most of high performance of all because, as the name suggests, it can last still even during the toughest trainings.

More seldom it is used the older models, made of leather with strings. To use them one must drill holes in the tusba through which the strings are passed, and the whole ensemble is mounted on the handle by tying the strings to the tsuru. Some use only a leather band to tie the tsuba onto the shinai. There is also a 2 in 1 model: the tsuba-dome that's part of the tsuba, made of plastic and having the rubber ring built in, but this is not too popular at this moment.

The leather parts – tsuka gawa, saki gawa, nakayui – are made of dear or synthetic leather. Tsuka gawa is hand or machine sewed. The length of the tsuka-gawa should correspond to the length of the forearm. Saki-gawa must have a minimum length of 50 mm; this rule has been introduced due to the number of accidents caused by the strips that have been released from the shorter saki-gawa (1 sun = aprox 30mm). Nakayui is a leather band of approximately 5-8 mm wide virgula and long enough to be wrapped around the bamboo strips 3 times virgula and then be tighten tightening with the 3 special knots. It must be positioned in such a way that the length of the datotsu-bu should be one quarter of the length of the shinai (the old rule: one third of the length of jin-bu).

Tsuru is made of synthetic string and can have any color. Traditionally it was made of silk. Komono, which is the small leather loop, was used more with the silk tsuru so the tsuru doesn't get damaged while folding. Chigiri is made of thin metal plate; its size depends on the thickness of the blades at the tusba side. Saki gomu is made of plastic or rubber. As for chigiri, it is used in different sizes depending on the space of the blades at the top.

Important things to be checked

Due to safety reasons, a shinai that is used in trainings or competitions must meet the following criteria:

• The blades should be in good condition (no splinters, cracks or breaks). A deteriorated blade CAN NOT be repaired (superglue, other sticking materials);
• The leather parts should not be damaged or broken;
• Tsuru must be intact;
• Tsuba must be mounted in the right position.

Special Shinai

There are special shinai used for different purposes: individual trainings, decorations, for trainers (uchikomi bo), etc. It's important that they are not used for contact exercises (jigeiko, shiai, shinsa!!)

For individual trainings, suburi for example, one can use the shinai that resembles a real sword, with curvature. Some use shinai with 4 or 6 wider bamboo stipes, that are thicker and heavier for strengthening the arms. For the same purpose, there are special shinai imitations made of wood mounted with leather parts.

Sometimes small shinai are used for decorations.