In Ancient China, when they were used in the extended form, could be used in the same conditions as other blade weapons such as the Sword or the Sabre, and however when it is invested, reducing the distance and getting greater effectiveness in more sheltered places at which the sword moved with more difficulty.
One of the features of the Knives Butterfly, is that it has an 'S' that forms a protection and extends the length of the handle, to cover several inches of the tip of the knife. Also, the portion that covers the grip, protects the fingers of the person holding the Knife cuts and injuries dropped by another weapon in combat.
The hook part of the guard, which protrudes several centimeters above the leaf, allowing the practitioner of Kung-Fu, to reverse the Knife with a quick movement of the thumb. In this inverted position, the knives block other weapons or are used to fighting in closed places where the martial artist does not have the ability to use the Knives in their full extension.