There is a good chinese article on the explanation of "black and white Wuchang" at
http://www.18zw.com/.../200503/260.htmBasically, in chinese mythology, the "black and white Wuchang" are the ghosts from the hell whose responsibilities are to pick up the ghostly spirit from the dead person and transport it to hell.
What is "wuchang 无常"? Wuchang refers to the escort or 'messenger' from the hell to transport a dead spirit from the hell to human world or vice versa.
Why must "Wuchang" be differentiated into black and white? And not yellow, purple or some other color? Basically, black and white are not due to the skin color or dressing color, but rather they are representation of "Yin 阴" and "Yang 阳" (dual forces in the world). The black represents the "yin", while the white represents the "yang". This is similar to the Taiji diagram's black and white, which was based on the theory of Yin and Yang.
Why must there be two "wuchang" and not just one?
Firstly, we need to figure out what is spirit 魂 and soul 魄. According to dictionary, spirit is a 'superstitious' saying, it refers to a "spiritual body" that leaves the body but still existing. Soul refers to the 'spiritual body' that still sticks to the body. Although most people tends to put soul and spirit together, but there are differences. The spirit refers to the spiritual essence while the soul actually refers to the spiritual force, which according to Yin-yang theory is the "Qi 气" (or breath).
When a person die, two 'wuchang' are needed because one of them is responsible for picking up the 'spirit' that leaves the dead body, while other other is responsible for 'dispersing' the soul in the body (by absorbing the soul). From then on, the 'dead spirit' is transported to the hell.
The Yin and Yang needs to be co-ordinated. Suppose Yang is "positive +" force while Yin is "negative -" force.
For a male, he consists of "Yin" spirit and "Yang" soul. If he dies, the white wuchang, which represents "yang", would pickup his "yin" spirit (yang attracted to yin force), while the black wuchang, which represents "yin", would disperse the "yang" soul in the body (yin absorbs/attracts yang force).
For a female, she consists of "Yang" spirit and "Yin" soul. If she dies, the black wuchang, which represents "yin", would pick up her "Yang" spirit (yin attracted to yang force), while the white wuchang, which represents "yang", would disperse the "Yin" soul in the body (yang aborbs/attracts yin force).
Edited by General_Zhaoyun, 01 September 2005 - 12:33 PM.