The Balisong, called a Butterfly knife in the West, and sometimes known as a Batangas knife, is a form of folding pocket knife with two handles that counter-rotate around the tang such that, when closed, the blade is concealed within grooves in the handles. In the hands of a trained user, the knife blade can be brought forth quickly using one hand.

Manipulations (flipping) are performed for art or amusement and require great skill. Translated from Tagalog, the word "Balisong" means "Broken Horn" (literally, "baling sungay") as the original Balisongs were made from carved animal horns and recycled knife blades. The name butterfly knife is a term coined in the United States much like "drumbox" for the kahon.

The history of the butterfly knife is uncertain, though three main ideas persist:

• The knife may actually have been invented by the French. The book "Le Perret" shows an obvious sketch of a balisong knife, and is dated 1710 A.D. The book itself suggests the balisong was developed in the late 1600's or early 1700's A.D.

• The knife dates back to around 800 A.D. and is a traditional weapon of the Filipino fighting art of Eskrima; however, it is not actually a prominent weapon in the art.

• The knife was invented around 1900 A.D. in the Philippines and spread by American soldiers returning from World War II.

Legal status

Because of its potential usage as a weapon in Western culture, and possibly due to its intimidating nature and rapid deployment, it has been outlawed in several Western countries.

• In Canada the possession of a butterfly knife is illegal.

• In England & Wales, The Butterfly Knife has been legally classified as an offensive weapon since January 1989. Possession of one is a criminal offense, and any imported are liable to be seized and prosecution may follow. The exception to this are knives of this type over 100 years old which are classed as antiques.
• In the Federal Republic of Germany the butterfly knife was outlawed by the new Waffengesetz which was introduced during the aftermath of the Erfurt massacre in April 2003. Thus buying, possessing, lending, using, carrying, crafting, altering and trading it is illegal and is persecuted by up to five years imprisonment, confiscation of the knife and a fine of up to 10.000€. Using a butterfly knife for crime of any kind is prosecuted by from 1 to 10 years imprisonment. Exceptional cases are if you are in service of the federal police, bank, customs, army or government, if it is registered that you are in danger or if you are an exceptional guest.

• In Hong Kong, the sale of full-size butterfly knives is illegal, but miniature versions can be legally obtained.

• In many U.S. states, it is illegal to possess and/or carry such a knife in public; indeed, doing so is a felony in some states, such as Nevada. In some states, balisongs fall erroneously into the category of a "gravity knife," "switchblade," or "dagger" although they are also occasionally outlawed by name. The knife is also illegal in California.

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