Aikido weapons
English version: 
Marco Giampetruzzi
The weapons used in the practice of the traditional Aikido of Iwama are JO, KEN and TANTO.
During the Founder's lifetime (1883 - 1969) firearms were forbidden in Japan, except for use during wartime. In daily life everyone needed to use weapon made from whatever can be easily found. A wood stick, of different thickness and length, was the more economic and functional weapon: try to think about a traveler who needed to keep off wild animals that he could encounter along the way; by sharpening its tip, the wood stick could easily become a short lance (NUHOKO). Almost everybody had a knife. Not anybody could afford an authentic Katana but, by means of carving a piece of wood, everyone could obtain a wooden katana which could be wielded and handed like a Japanese sword. These being the conventional weapons in Japan during the 19th century and the beginning of the 20th century, “O Sensei” worked out strategies of harmonization, defense and disarmament using these weapons.
The "Jo"
JO is usually 130 cm long and has a diameter of 2,5 cm. It can vary little in length and weight according to the personal requirements of its user and it is made of “white oak” which is a particular quality of Japanese wood that combines a relatively light weight with a great resistance to blows; this quality is very important in the practice of “Kumi Jo” when the jos cross one another or when the jo is used to sweep the ken, like in the “Ken tai Jo” practice. The jo cannot be too heavy or too long because unlike the other martial arts “O Sensei” conceived it so that it could be used like a “ken”.
The "Ken"
KEN means “Japanese sword”. In the study of Aikido it could be dangerous to practice with real swords; that's why during sword pratice we use the BOKKEN, the wooden sword.
The Iwama Ken is more or less a meter long (cm. 103) and weights approximately 750 grams; the ken, like the jo, is made of "Japanese white oak” and its tip is cut off for security reasons. Its weight can vary, depending if it is used in the solo practice, like in “suburi” or in the partner practice, like in “kumi tachi”. The ken can also be very heavy, like the one used in the “tanren uchi” practice (hitting repeatedly with the sword a training surface, like for example, a car tyre).
The "Tanto"
The TANTO (also known as TANKEN) is a wooden knife. In Iwama with passing of time tantos of different length came to be used, all of them had the tip cut off. In 1984 the medium length of a “Tanken” was approximately 30/35 centimeters. With passing of time this measure has gone more and more diminishing until in 2005 was reduced to approximately 25 centimeters. Kai-cho Saito Hitohiro prefers a “tanto” of small dimensions in order to diminish its dangerousness during the practice, especially when used to deliver frontal and lateral cuts.
