Jian, 剑, is an elegant Chinese sword and one of the few original weapons found in the art of Tai Chi Chuan. Small, precise circling motions are used. It’s also a weapon that is very hard to defend from. It’s use is very misunderstood and few people today practice it with the kind of movements that is needed to make it perfectly efficient in real, practical use.
Here’s a fascinating documentary about the Jian, it’s history and it’s place in modern China: