The tonfa is a long baton made from hard wood with a side handle that juts out from the shaft at a 90 degree angle.

The origin of the tonfa can be traced to ancient China and Thailand where it was originally used to as an accessory to a millstone. After being inserted into the millstone, the tonfa would be used to grind rice. Eventually, the tonfa made its way to Okinawa for the same purpose of grinding rice. Since Okinawa had a strong martial culture, it is no surprise that the tonfa was added to the many other farm implements based weapons of Japanese and Okinawan karate. This is because it can easily be incorporated into traditional punching and blocking.

What made the tonfa an important inclusion into Karate and Jujitsu was its ability to deal with bladed weaponry. Specifically, the long handles covered the forearms and could provide decent protection against sword swings. The offensive capabilities of the tonfa were also expansive and included thrusting, twirling, and Jujitsu style grappling techniques.

As it became a popular part of Okinawan karate, for blocking and punching, the tonfa was modified. The handle was adjusted so that the body of the tonfa would rotate if it was spun while the handle was gripped. This expanded its range for striking and made it more difficult to block because of its circular motion.

The tonfa is held by the short handle with the longer shaft running along the side of the forearm. When used for defense the shaft protects the arm and hand and the handle protects the thumb. It can also be held by each end of the shaft to block blows from other weapons such as swords. When used offensively, the tonfa can be swung in a circular motion so that the shaft strikes the target, or swung by the shaft so that the handle strikes the blow.

Today tonfas are used in conjunction with karate, usually in pairs. The tonfa is so effective as a striking and blocking weapon that it has been incorporated into the police force. A traditional Tonfa kata form is outlined here.