The MSN Encarta Dictionary defines a germinal vesicle as the enlarged nucleus of an egg before it develops into an ovum. No, one is not trying to discuss a medical term or something sexual or bisexual here, but the germinal vesicle means something totally different in inner alchemy (neidan) practice.
In the Book of Consciousness and Life (Hui Ming Ching) Richard Wilhelm and Cary Baines translation:
“The germinal vesicle is an invisible cavern which has neither form nor image. When the vital breath stirs, the seed of this vesicle comes into being; when it ceases it disappears again. It is the place that harbors truth, the altar upon which consciousness and life are made. It is called the dragon castle at the bottom of the sea, the boundary region of the snow mountains, the primordial pass, the kingdom of greatest joy, the boundless country. All these different names mean this germinal vesicle.If a dying man does not know this germinal vesicle, he will not find the unity of consciousness and life in a thousand births, or in ten thousand a eons.”
About two years ago, a young overseas Chinese from a South East Asian country had asked in a Daoist forum whether the germinal vesicle actually exists. He had by chance overheard the elders in his Daoist temple discussing about it. Since no one answered his query, I had said yes.
It exists in man. Those who practise neidan may notice or be aware of it after several years of continual correct practice.
What has been explained in the Hui Ming Ching as highlighted above contains the key to the understanding and awareness of where the germinal vesicle is located. Here could be some hints:
When the neidan practitioner is at rest, he or she may at times be aware of a bulge near the location indicated by the neidan adepts. If one touches the bulge before it disappears, which it will within a short period of time, it would immediately flatten. The bulge has the same shape when it appears now and then over the years at the same location.
Therefore the adepts were not wrong when they described the germinal vesicle as an invisible cavern which has neither form nor image. And when the vital breath stirs, the seed of this vesicle comes into being, when it ceases it disappears again. They had also indicated the exact location too; whether we can find it as usual is entirely up to our own practice.
According to the author of the Hui Ming Ching and the elders of the particular Daoist temple, it is important to know the germinal vesicle. Perhaps it is one of the signposts along the far journey to Tao. Well I do not know, but do watch out for it, there will be many other signposts, if you happen to walk along the same route as my Daoist friend and me. The signpost(s) will remain there forever and you cannot miss them unless you have used other paths for the neidan practice.
Note: The Hui Ming Ching is included in The Secret of The Golden Flower translated by W/B.