According to one source, “there is no name below the text the "Preface to Six Harmonies" and there is no evidence Dai actually wrote it. While most Xingyiquan practitioners consider the ["Preface"] to be a document of historical value, more and more researchers doubt its authenticity. Some even claim it is a forgery made out in Shanxi at the end of the 19th century. This, coupled with the fact that the Yue Fei Biography only mentions Zhou teaching Yue archery and not the spear, means Zhou's connection with the art is only legendary. In his book "Xíngyì Quán Shù Jué Wēi" (), author "Liu Dian Chen" () mentions that some military works wrongly consider Zhou Tong the founder of Xingyi.