This is not an in-depth study of ancient Chinese cosmogony as it requires a specialization of ancient philosophical writings and a close acquaintance with the rich folklore of China. However, it can be said for certain that the theories of yin and yang and the five elements are a part of the ancient Chinese cosmogony. First we have the five elements water, fire, wood, metal and earth. Water moistens downwards. Fire heats upwards.
Wood is both crooked and straight.
Metal can be changed into various shapes. Earth is for planting crops. Moistening downwards makes the salty taste. Heating upwards makes the bitter taste. Crookedness and straightness make the sour taste.