Butterfly swords

The butterfly sword (simplified Chinese: 蝴蝶双刀; traditional Chinese: 蝴蝶雙刀; pinyin: húdié shuāngdāo) is a short dao, or single-edged sword, originally from southern China, though it has also seen use in the north.

The blade of a butterfly sword is roughly as long as a human forearm, which allows easy concealment inside loose sleeves or boots, and allows greater maneuverability when spinning and rotating during close-quarters fighting. Butterfly swords are usually wielded in pairs. A pair of swords will often be carried side by side within the same scabbard, so as to give the appearance of a single weapon.

The butterfly sword has a small crossguard to protect the hands of the wielder, similar to that of a sai, which can also be used to block or hook an opponent's weapon. In some versions the crossguard is enlarged offering a second handhold, held in this position the swords can be manipulated in a manner akin to a pair of tonfa. They may also be used as brass knuckles when non-lethal application of the weapon is desired.

Traditionally, the blade of a butterfly sword is only sharpened along half of its edge - from the middle of the blade to the tip; this can be seen in all vintage specimens from the Qing dynasty. The blade from the midpoint down is left blunt so that it can be used to deliver non-lethal strikes and to block without damaging the sharpened edge. Butterflies were generally commissioned for individual martial artists, not mass-produced, so every set of swords is different, however an average blade today is about 11½" long with a 6" handle.

Butterfly swords are usually called 'butterfly knives' in English. However, they should not be confused with the folding balisong, which is also commonly called a butterfly knife. The Chinese word dao is used to designate any blade whose primary function is to cut and slash regardless of length. In some branches of Kung Fu, such as Wing Chun, butterfly knives are known as Baat Jaam Do (named after the system's form, literally 'Eight Chopping/Slashing Knives' in Cantonese).

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