As Zen began to change for various reasons, sometimes falling into stereotypes and clichés, a correction was called for. The kung-an (Jp., koan) was created to get behind words, called hua-t’ou, helping the Zennist to give up the habit of searching for enlightenment through words. Rather the uttering power which brought forth particular phrases in a kung-an was, itself, directly investigated which was before language, including mental thought. For example, the mysterious power which uttered the Chinese word “Wu”, which caused the subvocal sound in the mind of the Zennist, was investigated—not Wu. Unlike Western science, Chinese Buddhists believed in an animative principle which superseded phenomena and, by implication, language. By various practices this principle, under many different names such as ‘mind’, ‘ultimate reality’, and ‘suchness’, could be reached and cultivated. This nature or animative power, was exemplified in the so-called ‘three barriers’ which are as follows:

Brushing aside confusion to search out the hidden is only for the purpose of seeing true nature. Right now where is your true nature?

Only when you know your own true nature can you be freed from birth and death. When you are dying, how will you be free?

When you are free from birth and death, then you will know where you are going. When the elements disintegrate, where do you go?

Of course, comprehension of this true nature was the target of the Zennist—not phrases. But often the target was wrongly understood as was the precise meaning of the hau-t’ou of kung-ans. One arrant strategy was to construe true nature as silence or simple awareness. This amounted to a kind of therapeutic alienation. This strategy evolved into the teaching of ‘silent illumination’ which Dogen Zenji brought to Japan and developed. This was subsequently followed by the extreme emphasis on the act of physical sitting instead of free investigation, as it were, trying to merge with our true nature or animative principle. For this reason, staying in a Zen hall grew in importance so that Zennists might employ sit down meditation (Jp., zazen). Much of true Zen was, therefore, lost because of this practice.

When the kung-an tradition was passed onto Japan it became codified with stock answers. These Japanese Zennists did not realize that the whole point of the kung-an practice was to see the animative spirit which uttered the kung-an phrase or performed a strange gesture such as a teacher blinking his eyes.