Are threads as weapons real?

Question

There are multiple manga/anime that depict threads as weapons. For example in Basilisk :

Are these weapons based on real world counterparts?

Answer 1

Depends on the results you're looking for (slicing vs choking). Realistically there is no current application of any material (carbon nanotubes composites included) thin enough and with enough tensile strength to be the equivalent of razor wire/floss that can cut thru things as if they were pudding.

This sort of trope is likely to have been inspire in part by the garrote wire (sometimes also referred to as the strangulation wire). This was a preferred method of silent assassinations in the 17th and 18th centuries and especially in WWII by the French Foreign Legion, among other things.