The bokken or bokuto are wooden, mock swords created for use in the Japanese martial arts. Bokken refers to the double-edged mock sword, whereas bokuto refers to the single-edged mock sword. Whilst the initial use of bokken is unknown, and mock weaponry has a significant history, it certainly stretches back to the Muromachi period. Bokken or bokuto will vary in length and shape as they can be created to resemble any Japanese sword. Traditionally made from oak, bokken and bokuto must be made from a hardwood as flexible wood-made swords are termed shinai. For most of their history bokken and bokuto would be made by non-specialist woodworkers, but at the beginning of the 20th century formal production of the mock-swords was established in Kyushu. Today, it is believed that four bokken or bokuto workshops remain.