Soft sword, because his sword is as soft as silk, and his strength is not easy to master and use, he must be highly concentrated when practicing. So he belongs to the difficult type of fencing, which is completely different from the hard sword.

Liu Kun, a poet in the Jin Dynasty, wrote a poem praising soft sword in Poems for Lu Zhan: "What does it mean to make steel?" There are also traces of soft sword in Shen Kuo's Meng Qian Bi Tan in Song Dynasty. He said, "Bend as hard as a hook and it will be as loud and straight as a string", "You can bend it in a box and straighten it vertically".