There are four types of Tang swords, which are generally referred to as the sword systems that were equipped in the army during the Tang Dynasty of China.
As recorded in the clause of the duties of the commander of the arsenal in Volume 16 of the "Six Canons of the Tang", there are four types of swords: one is called Yidao, the second is Zhan Dao, the third is Hengdao, and the fourth is Moye.