When mountains lie to the south and water lies to the north, the land would be considered yang. If their positions were reversed, the land would be considered yin.
The Heaven Yang Grass was not grass in the strictest sense of the word. It couldn't even be classified as a plant. It had a similar shape with that of a newly sprouted bamboo shoot. Most of it was buried in the earth, with a curved tip of no more than three centimeters exposed to the surface.
There was a precondition to its growth. Only in sunny places where mountains lie to the south and water lies to the north and where an abundance of Pure Yang Qi gathered.
The Earth Yin Grass was exactly the opposite. While it was still a type of rhizome, it was shaped more like a sweet potato. It grew completely underground and would definitely have nine nodes.