A Variable Sword was an ultra-tech update of the monomolecular whip. Unlike its predecessor, the variable sword was perfectly legal as long as you were a soldier.
(Note: The background section of this page uses most of the same words s Terra Futura's page monomolecular whips to save time.)
The monomolecular wire was first popularized in science fiction. However, they did not become a possibility until 1990 when carbon nanotubes were discovered. Carbon nanotubes saw a whole lot of applications. They were in transistors. They were in artificial muscles. They were even in megastructures and space elevators. In the late 21st century, however, they saw use in monomolecular wires. Monomolecular wires were characterized by two characteristics. One was extremely high tensile strength. The other was that they were so thin that monomolecular wires were difficult to see. These were both features of carbon nanotubes. By the late 21st century, nanoscale manufacturing had been perfected, allowing a monomolecular wire to be created. A monomolecular wire made of carbon nanotubes was so thin that it was best used as a cutting tool. A monomolecular wire could cut through anything except another monomolecular wire or anything else with high tensile strength. Synthetic diamond (Note: There will be no page on synthetic diamond.) was used as a spool to handle the wire. While in science fiction, monomolecular wires were used by humans, in reality, only robots used them. Monomolecular wires were too dangerous to be handled by humans. They could lose a body part or even die. One infamous and highly illegal usage of monomolecular wire was as a whip. A monomolecular whip was similar to a conventional spool except there was a small weight at the end. The weight glowed red to show how far the wire went. This was a slashing weapon only. It could not make holes in a flat surface. If the right length, a monomolecular whip could slash through an enemy. It was highly illegal because even with carbon nanotube armor, a person could wind up losing a hand or his head. The latter would mean certain death. When the stasis field was invented, a safer, ultra-tech, update of this weapon was made called a variable sword.
Tech Level: 14
With the advent of the stasis field, a monomolecular wire could be held rigid like a sword. A variable sword could also switch between different lengths. The wire could go from very tough to virtually indestructible. Only gravity could affect it. It could slash, but not thrust. It remained straight anyway. Only the military had access to them. For something in the year 10,000 AD, that was certainly a good idea.