Jodo is one of the many martial arts native to Japan. Jodo employs as its primary weapon the jo, a hardwood short staff, from which the art takes its name. Jodo continues to be taught today, both in Japan and in the West, and is considered one of the koryu arts of ancient Japan.
History and Myth
Traditionally, the use of the short staff in combat is held to have originated in the early 17th Century with the samurai Muso Gonnosuke, a warrior famous for his use of the longer staff, the bo. Legend says that Muso met and dueled with Miyamoto Musashi, the swordsman who went on to compose the Book of the Five Rings. In the duel, Miyamoto was able to gain an advantage over Muso by blocking his long staff by crossing his swords, and then counter-attacking before Muso could recover. Musashi won the duel, but left Gonnosuke alive rather than destroy an obviously talented martial artist. Muso retreated to the hills to meditate on his first loss in combat. By inspiration or frustration, he broke his long staff into a shorter length, and descended from the mountains to challange Miyamoto Musashi a second time. In this second duel, the shorter length of Muso's staff made it possible for him to reply to Miyamoto's blocks in quicker fashion. Muso won the second duel, but returned the favor that had been done to him, leaving the famed swordsman alive to write his book. Legend holds that the defeats suffered in this pair of duels were the only losses either man was ever to suffer.
After his duel, Muso Gonnosuke went on to found the first school of jo-combat, which he called the shindo muso ryu jojutsu. As Muso's technique was developed to counter swordsmen, the school remained oriented around the sword, adopting many of the postures and strikes of the sword arts. However, the pole-arm flavor of the staff was retained, and the thrusts, sweeps, and other motions of the yari and naginata were incorporated as well. The shorter length of the jo was turned to the wielder's advantage, by employing numerous changes of grip and direction of motion that allow the wielder of a jo to take advantage of its reach while attaining a speed and versatility that a longer weapon could not match.
The main area of training is in disarming and subdoing an opponent wielding one or two swords, or another jo. Techniques include strikes, entangling and trapping, sweeps, entering, and receiving. This training is carried out through solo exercises of single and grouped manoevers (suburi and kata), and through paired practice (kumijo), which is primarily of fixed sequences of attacks and counters, but may include free-form sparring (randori).
Modern schools of jo technique call the art jodo, rather than jojutsu. Without opening up a very ugly can of worms, suffice it to say that arts ending in -do are usually considered arts suitable for personal development and enlightenment, with self-defense or combat skills a side effect. Arts ending in -jutsu are the old (pre-1600) samurai arts, meant first to be used to kill folks on the field of battle, and only later to worry about anything else. Very few modern teachers of anything teach 'real' -jutsu styles- and perhaps that is not such a bad thing!
The jo itself is a fairly simple and humble weapon. It is called either the short staff or the four-foot staff, and in size ranges from between fifty and sixty inches, typically. It lies between the long bo staff used in karate and other arts (properly called the rokushaku bo, or six-foot stick), and the very short three-foot stick (called hanbo, or half-stick, in Japan) used in Escrima and other arts. It is usually 7/8's of an inch to one inch in diameter, with untapered ends. The typical guideline for sizing a staff to its wielder is that the jo should stretch from the floor to just under the armpit, or to the nipple.
The jo was traditionally made from hardwood, and most modern jos carry on this tradition. Softer woods, and even a simple wooden dowel, may be used for solo practice of kata or suburi, but the lighter weight of these items may put their used at a disadvantage when using the genuine article. Furthermore, any jo that is to be used in partner practice must be sturdy enough to withstand strikes from the other partner without breaking or splintering. The surface of the staff should be smooth, unvarnished (as this tends to become sticky or slick when sweaty hands are applied), and free of cracks, splits, or splinters (which your hands will soon discover after passing the staff through your hands a few times!).
As a weapon, the jo is simple but formidable. Users of the jo train to strike at the nerve centers and other critical points of the body. A succesful thrust or strike to a nerve center (kyusho) can incapacitate an opponent if delivered correctly. Forthermore, a targeted strike by a hardwood jo can shatter or ruin the edge of a finely-tempered sword- while even a very powerful swordsman will be hard pressed to cut all the way through a hardwood jo. While a solid slash into the jo may ruin it as a striking weapon, usually the jo can absorb multiple slashes without breaking or splintering- and each cut that the jo stops is likely to damage the edge of a fine samurai sword. A determined attack by a swordsman on a jo-wielder in an even matchup is likely to leave both weapons useless, but represents a much greater loss to the swordsman than to the student of jodo!
Perhaps the most common realm where the jo is encountered today is in its use in the study of aikido. Morihei Ueshiba, the founder of aikido, was a student of the jo, as well as the spear and sword. The jo was incorporated as a training weapon in aikido, and towards the end of his life, Ueshiba prefered the weapon above all others for its purity and simplicity. Aikido use of the jo in training is often referred to as aikijo, and is based in jodo. However, the techniques of aikijo can be quite different, with more emphasis on the use of the jo against unarmed opponents, much fewer strikes and entangling maneuvers, and more throws that are fundamentally aikido moves using the jo as an intermediary. As such, the aikido applications of the jo are at once more constrained (by choice of target and method of attack) and much broader (as they do not rely solely on the mechanics of the staff) than those of traditional jodo.