The weapons arose due to restrictions placed upon the peasants that meant they could not carry arms. As a result they were defenceless and developed a fighting system around their traditional farming implements. There is speculation as to whether all of these weapons were derived from the farming tools, as examples of similar weapons have been found in China, pre-dating the Okinawa adaptations.
The bo is a six-foot staff, tapered at either end. It was developed from a farming tool called a tenbin: a stick placed across the shoulders with baskets or sacks hanging from either end. The bo, along with shorter variations such as the jo and hanbo could also have been developed from walking sticks used by travellers, especially monks. The bo is considered the 'king' of the Okinawa weapons, as all others exploit its weaknesses in fighting it, whereas when it is fighting them it is using its strengths against them. The bo is the earliest of all okinawa weapons (and effectively one of the earliest of all weapons in the form of a basic staff), and is traditionally made from red or white oak.
The sai is a variation on a tool used to create furrows in the ground, it appears similar to a short sword, but is not bladed and the end is traditionally blunt. The two shorter prongs on either side of the main shaft are used for trapping other weapons such as swords or bo. The sai originally reached Japan in the form of the jitte or jutte, which has only a single prong. Both are truncheon-like weapons, used for striking and bludgeoning. Sais are traditionally carried in threes, two are used in combat and the third is used as a precursor to the actual fight and is thrown at the enemy. There are many other variations on the sai with varying prongs for trapping and blocking, and the monouchi, or shaft, can be round or octagonal.
A nunchaku is two sections of wood (or metal in modern incarnations) connected by a cord or chain. there is much controversy over its origins, some say it was originally a Chinese weapon, others say it evolved from a threshing flail, one theory purports that it was developed from a horse's bit. Chinese nunchaku tend to be rounded, whereas Japanese are octagonal, and they were originally linked by horse hair. There are many variations on the nunchaku, ranging from the three-sectional staff (san-setsu-kon nunchaku), to smaller multi-section nunchaku. The nunchaku was popularized by Bruce Lee in a number of films, made in both Hollywood and Hong Kong.
The tonfa is more readily recognised as the police nightstick. It supposedly originated as the handle of a millstone used for grinding grain. The tonfa is traditionally made from red oak, and can be gripped by the short perpendicular handle or by the longer main shaft. As with all Okinawa weapons, many of the forms are extensions of 'empty hand' techniques, adapted for weapons combat.
The final major Okinawa weapon is the kama; the only one to possess a blade. It is the traditional farming sickle, and considered the hardest to learn due to the inherent danger in practising with such a weapon. The point at which the blade and handle join in the traditional model normally has a nook with which a bo can be trapped, although this join proved to be a weak point in the design, and modern day examples tend to have a shorter handle with a blade that begins following the line of the handle and then bends, though to a lesser degree than the difference in orientation of the traditional model; this form of the kama is known as the natagama.