The butterfly sword was developed early in Chinese history and popularized during the Manchu dynasty. The term "butterfly" derives from the fact that two swords are often carried in the same scabbard, and when drawn the blades pull apart like the wings of a butterfly.
The blade itself is short: on the order of twelve to eighteen inches long, and is generally two to three inches wide. The sword has a very pronounced guard that extends along the back edge of the blade. This allows an experienced swordsman to deflect attacks and control his opponent's weapon, making him a match for a more heavily armed adversary.