A balisong, also known as a fan knife, a butterfly knife or a Batangas knife, is a folding pocket knife. Its distinct features are two handles rotating in the opposite direction around the silk, so that when closed, the blade is concealed in the grooves of the handles. A balisong with the lock on the “safe” handle, opposite the cutting edge, is called a Manila file. Balisong was commonly used by Filipinos, especially those in the Tagalog area, as a self-defense and pocket knife. A common stereotype is that a Batangueño wears one wherever he goes. Hollow ground balisongs were also used as razors before conventional razors were available in the Philippines. In the hands of a trained user, the knife blade can be used quickly with one hand. The manipulations, called “flipping”, are performed for art or amusement. The blunt versions of these knives, called “trainers”, are for sale to practice tricks without risk of injury. The knife is now illegal or restricted in some countries, often under the same laws and for the same reasons that leverage knives or concealed weapons are restricted, and in their country of origin they are no longer as common in urban areas .
The name of Tagalog, “Balisong”, seems to have emerged after the Second World War, when artisans from a Filipino barangay named Balisong began making knives for sale to the US military. The Balisong knife would have been an adaptation of a French folding knife called “The Foot of the King”, a rule of a standardized foot, sometimes including a blade, which was in official use in France from 1968 to 1999. The Balisong knife has may have been introduced to the Philippines towards the end of the Spanish occupation after the metric system was adopted in the Philippines, because it was also called “veinte y neveve” because it is 29 centimeters long when open .
Although the meaning of the term balisong is not entirely clear, a popular belief is that it derives from the word tagalog sungay (literally “broken / folded horn”) because it was originally made of carabao carabao and deer horn . Balisong is also the name of a barangay in Taal Municipality, Batangas Province, which became famous for making these knives. It is said that the traditional balisong is called veinte y neveve because they are 29 centimeters long when it is opened, while another story says that it bears the name of a lone Batangueño who fought 29 attackers using one. These knives are also called “fan knives” and “butterfly knives” of the movement and “clatter” of the sound they make when they are opened and closed.
There are two main types of balisong construction: “sandwich construction” and “canal construction”. Sandwich balisong knives are assembled in layers that are usually pinned or screwed, although a ball bearing system can sometimes be used. They allow the pivot axes to be adjusted more firmly without binding. When the knife is closed, the blade lies between the layers. For a canal built balisong, the main part of each handle is formed of a single piece of material. In this handle, a groove is created (either by folding, milling or integrally cast) in which the blade rests when the knife is closed. This style is considered to be stronger than sandwich construction. Some of the traditional butterfly knife blades in the Philippines were made from steel taken from the railways giving them a decent amount of durability and hardness, while others are made from recycled leaf springs of the vehicles. . Some balisongs, like Benchmade 51, do not use Tang Pins. Instead, he uses “Zen Pins”, which are two small pins embedded in the balisong handles that come into contact with the bottom of the blade.
First constructed in 1905 in Batangas, Philippines by Perfecto de Leon, the balisong gained mass exposure after World War II when the Batangueno bladesmiths earned a living providing custom crafted knives to American servicemen stationed in the Philippines at Clark Air Force Base and Subic Naval Base.” Balisong knives have been manufactured in Batangas province in the Philippines for many decades. According to an article on Balisong manufacturing in Mark Wiley’s book Arnis: Reflections on the History and Development of Filipino Martial ArtsBy Mark Wiley (2001), one craftsman is quoted as having made balisong for over 40 years. An American company, Balisong USA (now named ‘Benchmade’), claimed to have started manufacturing balisongs in the late-1970s.