From an analysis of the use of colour in hero:

Depending upon its context, color has symbolic meaning in Chinese culture, and is associated with the five elements in traditional Chinese lore. According to Chinese ideology, red is the color of fire, and is associated with celebrations and all things auspicious. Yellow symbolizes earth, which promotes growth. It is also symbolic of power and authority, since the Chinese word for yellow is a homonym for the word royal, and the use of the color yellow is therefore limited to royalty. Green and blue are both associated with the element of wood, representing growth, harmony and longevity. The Chinese use the same word for sky blue and the green of natural flora. White represents metal, and symbolizes sorrow, grief, death and mourning. Black is associated with the element of water and symbolizes darkness and evil.

In many of his films, Zhang Yimou has used the color red as a means of making a vibrant symbolic statement. However, according to the fact file on IMDB.com, the spectrum of the color motif in Hero has been expanded to include red as a symbol for imagination, blue for perceived reality, white for truth, and green for enlightenment and peace.

Link: http://www.thingsasian.com/stories-photos/3054

PS - I'm not suggesting we go anywhere near "Asian" themes