The longest sword ever made, based on historical records, is the Zhanmadao. The Zhanmadao, also known as the "horse-cutting saber," was an exceptionally long and heavy sword used in ancient China. It is often associated with the Ming Dynasty (1368-1644) and was favored by cavalry units.

The length of the Zhanmadao varied, but it typically measured around 2 meters (6.6 feet) in total length, with the blade constituting the majority of that length. The blade alone could measure over 1.5 meters (5 feet). The Zhanmadao had a long handle to accommodate the use of both hands for wielding.

The primary purpose of the Zhanmadao was to deliver powerful strikes and sweeps from horseback, targeting both enemy soldiers and their horses. Its size and weight allowed for effective cleaving through armor and creating a wide area of impact.

The Zhanmadao represents an extreme example of an oversized sword, designed for specific battlefield conditions and combat tactics. Surviving examples of the Zhanmadao can be found in museums and private collections, showcasing the impressive size and construction of this historical weapon.