Chinese, "critical phrase" or "head of a word" indicating the source from which thought emerges (compare with the Greek Logos, which means the same thing). Hua Tuo is known in Korean as hwadu, and in Japanese as wato. Hua Tou is an approach to meditation that emerged from Chinese Buddhism in the twelfth century. In this method, one mentally posits an unanswerable question, continually, without engaging the intellect, while maintaining sincere interest in answering the question. Example Hua Tuos include, “Where was I before birth? Where shall I be after death?”, "If you return your bones to your father and your flesh to your mother, where, then, would you be?", "Which is your original face?", and "What is Wu?" or simply, "Wu." There are two Chinese words wu: 1. "not, no, nothing, emptiness." 2. "enlightenment, to awaken to the fact, to understand." Samael Aun Weor wrote of the Hua Tou method in his books The Doomed Aryan Race, Parsifal Unveiled, and Gnostic Magic of the Runes.

Tie Shan wrote: [...] "I then went to see Hsueh Yen and I followed his instructions about the way to meditate on the word Wu. On the fourth night, perspiration surged from my whole body, and so I felt comfortable and light. I remained in the meditation hall, concentrated, without exchanging a word with anyone. Afterwards, I saw Miao Kao Feng who told me to continue meditating on the word Wu without rest day or night. When I got up, before dawn, the Hua Tou (the purpose of the word Wu, the essence of this phrase) immediately presented itself before me. As soon as I had some drowsiness I came down off of my seat. The Hua Tou (that is to say the word Wu) accompanied me while I walked, while I prepared the bed or the food, when I took the spoon or when I put aside the chopsticks. It was with me all the time, in all my activities, day and night. If one succeeds in fusing one’s mind into a continuous and homogeneous whole, enlightenment is assured." - Samael Aun Weor, Parsifal Unveiled