Rice vinegar
Chinese rice vinegars are stronger than Japanese ones, and range in colour from clear to various shades of red and brown. Chinese and especially Japanese vinegars are very mild and sweet compared to distilled and more acidic Western vinegars which, for that reason, are not appropriate substitutes for rice vinegars.
White rice vinegar is a colourless to pale yellow liquid, higher in vinegar content and more similar to Western vinegars, but still less acidic and milder in flavour.
Black rice vinegar is very popular in southern China. Chinkiang vinegar, which originated in the city of Zhenjiang in the eastern coastal province of Jiangsu, China, is considered the best of the black rice vinegars. Normally black rice vinegar is made with black glutinous rice (also called "sweet rice"), although millet or sorghum may be used instead. It is dark in colour, and has a deep, almost smoky flavour. In addition to Zhenjiang, it is also produced in Hong Kong.
Black rice vinegar really nice, the closest I would say is a cross between sherry vinegar and balsamic vinegar.
Red rice vinegar is darker than white rice vinegar, and paler than black rice vinegar, with a distinctive red colour from yeast rice. This vinegar has a distinctive flavour of its own due to the red mold.
In Chinese cookbooks, ½ tablespoon of Western distilled white vinegar is stated to be equivalent in strength to 1 tablespoon Chinkiang vinegar, and recipes which call for 4 teaspoons of red rice vinegar could be substituted with only 3 teaspoons of white vinegar.