It is debated whether the balisong design originated in the Philippines or in Europe. Some people point to its longtime use in the Filipino martial arts, and the balisong's place in Filipino culture and tradition. Others point to early European documents showing the existence of the balisong in Europe. The leading theory among researchers is that the balisong is a French design, and was carried to the Philippines on Spanish ships somewhere around the 18th century. It is also possible, however, that an indigenous Filipino design somehow made it to France. Regardless of origin, the balisong is popular in Filipino culture and tradition. It is not uncommon to see balisongs in use by fishermen, and there is a longtime cottage industry in the Philippines--dating back to at least the second World War--dedicated to making balisong knives from spare parts and available materials. Of course the balisong also has a role in the Filipino martial arts of kali, escrima, and arnis.