This section covers the categories by which the correspondence traditions sort the material world: the classical elements and the Japanese godai, the directions, the seven metals of alchemy, gemstones, plants, colours and incense.
These are the building blocks that make a system of correspondences usable. Once fire, water, air and earth (or wood, fire, earth, metal and water) are fixed, everything else (a planet, a direction, a stone, a herb, a colour), can be sorted under them, and a practitioner can move from one to another: this planet, therefore this metal, this day, this incense.