There is an ongoing interesting discussion in the Daoist section of the Tao Bums forum on the subject of Valley Spirit (Gu Shen in pinyin).
The debate started on whether Chapter Six of the original Tao Te Ching contains the term, ‘Valley Spirit’ or ‘Valley-water Spirit’. The current widely accepted text uses Valley Spirit while the MaWangDui (Early Han) silk text contains the term, Valley-water Spirit instead. It could be just a matter of semantics. Since what is the difference between a valley and a valley with water? After all when it rains, water will still flow down the mountain to the valley below. Researching the semantics by pedant scholars will not provide any further clarity. Probably of more importance is the real meaning of Valley Spirit(s).
There are various technical terms in the Tao Te Ching, meant only for cultivators of Tao and/or neidan practitioners, of which brilliant minds or whiz kids (Wang Bi for example) will not be able to penetrate unless they also cultivate or practise. And one of those terms is that of ‘Valley Spirit(s)’.
No matter how intelligent and diligent we are, theories will remain just that until what Laozi taught in the Tao Te Ching is put into practice. Both the Daoist and Chinese Buddhist term for the basic practice is called self cultivation (siu hang). Without self cultivation, there is no cultivation of Tao and/or neidan practice. Without this higher level of cultivation or practice, valley spirits will forever remain unknowns!
Since Valley Spirit is a phenomenon or a Tao signpost that can be witnessed and experienced by a neidan practitioner who has good aptitude according to Lu Dongbin in the Secret of the Golden Flower. Probably this would explain why Laozi in Chapter Six (6) of his Tao Te Ching indicated that ‘The Valley Spirit (s) never dies’. For how could the Valley Spirit die if the phenomenon can be witnessed or experienced by neidan adepts down the millennia?
In case of doubt, Valley Spirits are also inferred to by Lu Dongbin in his ‘Hundred Character Steele’; and by an unknown Daoist adept in ‘A directory for the day’; as well as by the Buddha in the Shurangama Sutra. Whether Zhuangzi has had inferred to the term or not in one of the writings is debatable since his description of the phenomenon differs. But how would I know?
The good thing about deep and profound studies – that of the Tao and of the Yijing - is that those who do not know cannot hoodwink or ‘madoff’ the learned and the wise!