The butterfly knife can be best described as a short dao, or also a blade with a single edge. It is originally from the South of China although it has been used in the North as well. The length of the blade in the butterfly knives is around the length of a human forearm. This aids in concealing the respective sword in the inner sleeves or also in the boots and allows gives its user an advantage in terms of maneuverability. These butterfly knives are mostly used in pairs meaning that one pair of these swords is most probably going to be carried side by side inside of the same cover. This gives an appearance to the people that there is only a single weapon and not two.
The butterfly knives also has a little crossguard that aids in protecting the hands of its user. It can also be described as being kind of similar to a sai that is capable of both blocking and hooking an opponent's weapon. They may also be used as a knuckle duster when non-lethal application of the weapon is desired.
By tradition, the butterfly knives has a blade that is sharpened only hallways across the edge – that is from the middle towards the tip of the blade. The blade that goes from the middle towards the handle is blunter as compared to the top half of the swords blade. The blunt of the lower half of the sword is left so that it can be used for delivering non-lethal strikes and also for blocking successfully without any damage to the sharpened edge. The blade is 11½"long and the handle is 5"long.
Butterfly swords are also commonly known as the 'butterfly knives' in the English language. The respective butterfly knives should not be at any cost confused with the regular folding butterfly knife. The Chinese word dao is used for the designation of a blade that is used for cutting and slashing regardless of the length of the blade. There are several sub categories of Kung Fu, namely Wing Chun and Wing Tsun, in which the butterfly swords are popular as the Baat Jaam Do (they are named after the Systems form, that literally means 'Eight Chopping/Slashing Knives').
Butterfly swords are mostly used in many Chinese martial arts, such as Wing Chun, Lau Gar and also the Hung Gar as has been aforementioned. When it comes to Wing Chun, there is a much notable aspect of butterfly knivesfighting as it is basis for all other weapons.
The Butterfly knives have become much famous all across the East owing to the Spanish colonization. The Philippines had been much famous for the manufacture of these durable butterfly knives.