The Jo is a short staff weapon commonly slightly over four feet in length and about one inch in diameter. Different martial arts system use slightly different lengths and diameters, but the above measurements are pretty typical for the Jo.
A Jo can be made from several different types of wood or can be constructed from metal, fiberglass, or any other rigid material. Many of these weapons are good for some forms of practice but are unacceptable for use in what is referred to as contact work where one weapon strikes another. A weapon that is not suitable for contact work may shatter upon contact, sending sharp pieces of wood (or metal) flying and potentially causing permanent injury or death. To help ensure the overall safety of everyone in a Dojo we insist that all weapons be inspected before they can be used and that only weapons considered to a contact weapon may be used for weapon-on-weapon practice.
We provide weapons that students can utilize for training, but many students wish to acquire their own weapon so they have a weapon to practice with at home and so they can become intimately familiar with the feel of a specific weapon. Here is some background information for those who may wish to purchase a weapon.
A Jo will ideally have a length that is equal to the distance from the floor to your armpit when the arm is held in a relaxed manner at your side. For most adults this results in a Jo that is somewhere between 46 and 56 inches in length. For children this length can be quite a bit less, which can present a safety issue. When purchasing a Jo you may be able to specify the length of the weapon, but commonly you will find a weapon that has a predefined length. This is often about 52” but can vary a few inches either way. The specific length is not that critical as long as the weapon is in the 46 to 56 inch range. Young children should normally purchase a weapon of this size as well but would probably elect to have a weapon on the smaller end of the scale. Students may opt for a weapon with different dimension in some situations (for example, to train for tournaments or exhibitions) but generally speaking weapons within the defined size range are preferred. If you have a question regarding size please do not hesitate to ask your instructor.
The diameter of a Jo weapon is another measurement that needs to be considered. Some Jo are thinner than others, and in some cases a Jo will be thicker in the middle and then taper to a smaller diameter toward each end. Our standard weapon has a diameter of one inch and is not tapered (it should have a uniform diameter over its entire length). Our standard diameter is one inch.
Students who wish to practice for tournaments or demonstrations may use a weapon made of any rigid material with or without a taper while training in the Dojo. Such weapons may not be used for any form of contact work. See below for more information on Jo Uses and Restrictions.
Many Jo weapons on the market are not acceptable for contact work in the Dojo. Wooden weapons that appear to have a dark brown or reddish color are commonly made of American Red Oak. Unfortunately, such weapons are everywhere on the Internet. These weapons are known to shatter or splinter when impacted soundly and are therefore permitted in the Dojo only under specific circumstances. A Jo must be manufactured to be a Jo. A wooden dowel, broom handle, or other wood stick should never be used. There are some specific woods that are known to produce good, reliable, and relatively safe Jo weapons. These woods are Japanese White Oak, also called Shiro Kashi (not American White Oak), Hickory and a few more exotic wood species. Please consult with your head instructor if you are considering purchasing a weapon of any other wood variety to ensure you purchase a weapon that will not be a wasted or potentially dangerous investment.
Traditional Jo weapons are either round, square, hexagonal or diagonal in shape (cross section). Round is by far the most common, though you may see the other shapes on occasion. Modern Jo weapons may be made of metal or other light materials and are commonly used for demonstrations or tournaments because they are often decorative and can be wielded with amazing speed and dexterity. Such weapons are not authorized for contact work in the Dojo (but may be used for tournament or demonstration practice) as they may be damaged by, or cause damage to, a hard wooden weapon.
Every weapon brought into your Dojo must be inspected by the Head Instructor or an authorized instructor. There can be no exceptions. A weapon that has not been inspected may not be employed in any fashion in the Dojo.
Inspections will examine the weapon for its material composition, design, and integrity. The goal is to ensure the safety of everyone in the Dojo. Following the inspection the weapon will be declared to be either a contact or non-contact weapon. Contact weapons may be used to make physical contact with other contact weapons. Non-contact weapons may never be used to strike, block, or otherwise contact another weapon or strike any rigid object, including training bags, equipment, floors, posts, or walls. And of course, no weapon should be used to strike others in the Dojo.
A Jo weapon may be classified as a contact weapon if all of the following are true.
- The weapon is made from an approved contact hardwood species
- The weapon has a length within the prescribed range of 46 to 56 inches
- The weapon has a uniform diameter of one inch
- The weapon is in sound physical condition without cracks, major divots, or potential points of failure
No Jo weapon made of or containing any metal may be classified as a contact weapon. Such weapons should never be employed in a manner where they may contact another weapon. Some metal weapons, particularly those made of aluminum may be severely damaged if they contact a hard wooden weapon. Other weapons made of steel or similar materials may readily shatter or splinter even a contact wooden weapon. As a result we do not allow any metal weapons, or weapons with any metal content, to be used for contact work.
Any weapon that does not meet the above contact weapon criteria will be classified as a non-contact weapon. Non-contact weapons made of wood or simulated wood materials must be marked to clearly indicate they are a non-contact weapon. Our standard method for identifying such weapons is to apply bright red paint or tape to both ends of the weapon. Your Dojo may elect to use a different method for clearly identifying such weapons. Whatever marking system is used should enable anyone wielding or who may potentially strike such a weapon to readily identifying it, even from a distance of ten feet, as a non-contact weapon. No practitioner should ever use such a weapon to strike, block or otherwise contact another weapon or forcefully contact another object such as a bag, wall, post, or floor.
The weapon owner must be clearly informed as to whether a weapon has been classified as a contact or non-contact weapon at the conclusion of the inspection. The owner should also be briefed as to the meanings of these terms.
When a weapon has been successfully inspected it may then be utilized for its authorized purposes. Non-contact weapons that require marking should either be marked during the inspection process or before the weapon is brought back to the Dojo a second time. In either case, the weapon may not be used for contact purposes.
If you bring a weapon into the Dojo you agree that the weapon can be inspected by any qualified inspector at any time. Instructors will from time to time inspect all weapons to ensure they have not become damaged or otherwise represent a safety risk to the practitioner or others after repetitive usage. These inspections are meant to be routine and in no way should be considered embarrassing or punitive. Everyone will have his or her weapon inspected several times each year. We suggest that you carefully observe and ask questions during such inspections so that you can learn how to properly inspect the weapon yourself. You should then inspect your weapon every time you pick it up.
Jo Uses and Restrictions
Both contact and non-contact weapons may be used for individual practice (for example, Kata practice or skill and handling drills). They may also be used when practitioners train for tournaments or demonstrations in which a specific weapon design and/or construction is advantageous. Therefore any contact or non-contact weapon can be used for any non-contact work.
Only an inspected and approved contact weapon may be employed for contact work.
We suggest that students consider purchasing a contact weapon when they wish to acquire a Jo weapon. It is useful for most forms of training and will avoid the temptation to use a non-contact weapon for contact work. You should ask your Head Instructor about where you may acquire a quality contact weapon. He or she should be able to recommend several sources. Once you have a contact weapon you may subsequently decide to purchase a specialty weapon that will facilitate other specific forms of training. We firmly recommend that students acquire a contact weapon as their first weapon.
The parts of the Jo have specific names with which you should become familiar. The flat ends of the Jo are called Kontei. This is a term you will encounter again with future weapons. The main shaft of the weapon is called the Monouchi, again a term you will encounter frequently in other weapons. The center of the cylindrical Jo body is called the Chukon-bu. You may at times see the very end of the weapon just outside of the Kontei referred to as the Kissaki. The Nigiri refers to a grip point and this (these) location(s) can vary greatly from one moment to another when using the Jo. The picture to the right above shows two Nigiri on either side of the Chukon-bu.