Master Hua's explanation on the structure of “Tao”（道）
The Chinese character Tao（道） has two short strokes on top representing yin and yang. If the character for “person”（人） is taken apart, it becomes one yin and one yang. These two strokes are the character ren（人） “person” inverted. Cultivating the Tao means turning around and going against the current.
Going along the current is birth and death; going against it is Nirvana. The characterni（逆）, “going against,” also has the two strokes on top representing “person,” because it is a person who decides whether to go along or to oppose the current.
In the character for Tao, beneath the two strokes is a horizontal line（─）. This is the Chinese character “yi”, which means “one.” Where do we find the Tao of being a person? We start with One, the basic substance of all numbers. Where did the One come from? Zero. Zero has no inside or outside, no beginning or end; it sweeps away all dharmas and is apart from all appearances. “Expand it, and it fills the universe; roll it up, and it hides away secretly.” The Zero is the beginning of all things.
To put it more plainly, the Zero is our inherent Buddha-nature. It is the great, bright, perfect treasury of light. It can be tinier than a speck of dust, or greater than the Dharma Realm. It can be limitlessly great and limitlessly small; it has no bounds.
When people do not follow the rules, the Zero breaks up and turns into One. When there is only Zero, there are no numbers. The numbers start with One. In the beginning, there is only the round, bright circle, and then it turns into the One, which is both yin and yang. “One yin and one yang make the Tao. Excessive yin or excessive yang causes sickness.”
Cultivation of the Tao must begin with One, and with searching for one's own self. The word zi（自）“self” is the character mu（目）“eye” with a stroke added on top. This tells us to look within, to turn our eyes inwards, not to look outwards. When you add the radical for “walking ”（这）, it becomes the character Tao（道）“path.”
It becomes the Tao, or Path, only when it is walked. Thus when Han Yu says in the essay “Yuan Tao”（“Path to the Origin”）, "A path goes from one place to another." People form a path by walking it; to walk the spiritual path, we must practice with serious effort. If we want to return to the origin, we must go from One back to Zero.
When the One is attained,
All things are settled.
When we return to the Zero, we return to our original countenance; then we will be able to turn the wonderful Dharma wheel.