虛雲和尚是對近代漢傳佛教有甚深影響的一位禪宗大德。自大慧宗杲倡導無字話頭的參究，宋代以後看話禪儼然成為禪宗的主要修學法門，如大慧說：「只這一（無）字，便是斷生死路頭底刀子也。」虛雲和尚亦提倡參話頭，但他對話頭的意涵解釋到：「所謂話頭，就是一念未生之際；一念纔生，已是話尾。」與大慧宗杲以來，將一個字或一句話視為話頭的說法有所差異。本文將虛雲和尚的看話禪法分為兩個階段來做探討。第一階段為疑情的起發與第二階段的「看話頭」。希由透過虛雲和尚在這兩階段所分別強調的重點，瞭解其看話禪法之特點。同時藉由探討虛雲和尚對話頭意涵的闡釋，分析「一念未生」的論述如何形構出其看話禪之特色。虛雲和尚說：「能看到一念無生，是名真看話頭。」筆者將由此分析虛雲和尚所闡述的看話禪要旨，同時對照大慧宗杲的「無」字話頭，瞭解二者在看話禪所分別強調的要點，從而論述虛雲和尚如何從看話禪的原理來說明「看話頭」，提出「所謂話頭，就是一念未生之際」的論述。學者陳兵在〈虛雲和尚的禪學思想〉提到：「關於參話頭的方法，自大慧宗杲以來，述說已多，然對其原理，揭示甚少，虛雲和尚對看話頭的原理作了明白的解釋。」陳兵認為「一念未生」時是為清淨心的說法，早見於天台宗二祖慧思大師，但筆者認為虛雲和尚的「一念未生」思想之提出，與六祖惠能的「無念」思想應有更直接的關聯。本文擬從虛雲和尚的教說分析，論述虛雲和尚如何以「話頭」的意涵，融通清淨心與般若思想，承繼六祖惠能的「無念行」。同時，筆者擬以虛雲和尚所引用的《楞嚴經》、《大乘起信論》等教說，進一步論述「一念未生」在虛雲和尚之教理、教證所扮演的中介角色，及其與默照禪法之相通處。

Master Xuyun is a great Chan Master who has a great influence on modern Chinese Buddhism. Kanhua Chan (看話禪) has been known as the important doctrine of Chan school from Song Dynasty since Dahui Zonggao advocated this method. Dahui mentioned that making good use of the word ＂Wu＂ (nothing, 無) in Huatou (話頭) meditation could release us from the cycle of rebirth, so he regarded the word ＂Wu＂ as the key to Huatou. Master Xuyun also advocated the practice of Kanhua Chan but he proposed Huatou a new definition as a state of ＂one thought not arising,＂ (一念未生) i.e. when a thought has come up, it can't be counted as Huatou anymore. This viewpoint is quite different from that of Dahui. In this essay, I will try to analyze Xuyun's teachings of Kanhua Chan in two stages. The first is about the arising of doubt sensation; the second Kan Huatou itself. Through the approach of Master Xuyun, we can have a clear understanding about how his Huatou thought characterizes his teaching on Kanhua Chan. A comparison between Xuyun and Dahui discussed reveals that they have emphasized on their teachings differently. In my opinion, Master Xuyun's concept of Huatou has been immensely influenced by Huineng's idea of ＂Mindlessness.＂ (free from false thought, 無念) Basing on the concept of ＂Mindlessness,＂ Xuyun gave Huatou a specific definition and clear explanation in order to guide students to take the true meaning of Huatou during their ＂Chan practicing. ＂In his essay Chenbing mentions that a lot of teachings about Kanhua Chan has been practiced, but few of them it's true meaning has been inquired deeply, except for Master Xuyun who has clear explanation and teachings of Huatou. Chenbing also mentions that the content of Xuyun's theory about ＂one thought not arising＂ is equal to ＂nature mind,＂ which has been initially raised by Tiantai school's Master Huisi. In my opinion, Xuyun was influenced more by Huineng's idea of ＂Mindlessness＂ than by Master Huisi. Thus, this article will not only focus on Master Xuyun's teachings about Huatou but will explore how Master Xuyun is inspired by Huineng's idea of ＂Mindlessness＂ and proposes his theory of ＂one thought not arising.＂ This paper will also discuss some Xuyun's interpretations of The Surangama Sutra (楞嚴經) and The Awakening of Mahayana Faith (大乘起信論), and go further to investigate and analyze how his “one thought not arising＂ theory bridges the teachings and practices of Kanhua Chan taught by Xuyun Master. In addition, I'll also explicate the common perspective between ＂one thought not arising＂ and Mozhao Chan.