26. A Fine Sword That Was Supplanted by a Simpler One
In the period from the sixth to fourth centuries BC, Jian blades were usually about two feet long. They had spines made of bronze with low tin content, while bronze with higher tin content was used on the edges. That resulted in a sword with a hard cutting edge, that retained a flexible spine to absorb shock. By the fourth century BC, bronze jians began to be phased out. They were replaced by steel jians that used high carbon content steel on the cutting edges to make them hard, and softer steel on the core for flexibility.
Bronze does not allow for long blades, because the metal is not strong enough to withstand stress. So by necessity, bronze swords had to be short and sturdy. Steel does not have such limitations, and its introduction allowed for longer blades. Steel jians featured longer handles than their bronze predecessors for two-handed use, and grew to about three and a half feet long. Some measured up to five feet and three inches. By the first century AD, however, the simpler and easier to use dao sword began to supplant the jian. By the third century AD, the process was completed, and the jian was restricted to the Chinese aristocracy and to ceremonial court usage.