T'ai chi ch'uan
According to some schools of T'ai chi ch'uan, Xu is considered to be the Tao Yin teacher of Zhang Sanfeng, whom they say later created the martial art of T'ai chi ch'uan. Other schools hold that Xu himself was a T'ai chi ch'uan practitioner, and that the style Xu Xuanping passed down was simply called "37", because it consisted of 37 named styles or techniques. During this time it was also known as Chang Quan 長拳 or "Long Boxing" as a reference to the flowing power of the Yangtze River 揚子江, (which is also known as the Chang Jiang 長江 or Long River). He had a disciple called Song Yuanqiao who passed the Song Family T'ai chi ch'uan system down through the generations to Song Shuming.