There Are Differences Among Reciting the Huatou, Looking at the Huatou, and Investigating the Huatou

Watching the huatou is cultivating the power of meditative concentration (samādhi), letting the mind abide before the words of a sentence, without words and language emerging. When the power of concentration is insufficient, words and language will all emerge, and the inner voice is unceasing—this is reciting the huatou. Therefore, it is only when there is no power of concentration that the mind repeatedly repeats a sentence over and over; when there is power of concentration, both the inner voice and the mental image of words must disappear.

When the power of concentration in watching the huatou is sufficient, one can then investigate the huatou, probing into the meaning of this sentence. Words and language almost never appear, and one will not engage in emotional thinking and intellectual interpretation; only then can there be true realization through enlightenment, rather than realization through understanding. For a person with insufficient power of concentration, if they are to attain enlightenment, it can only be realization through understanding.