In the entire production process of shiitake mushrooms, there are mainly two stages: the first stage is to cultivate the mycelium, and the second stage is to use the cultivated mycelium for planting. The production of mycelium can be divided into three steps: the first step is to cultivate the mother mycelium (also called primary mycelium or test tube mycelium) by using methods such as spore separation, tissue separation, or mycelium separation from the substrate to obtain the mother mycelium. The second step is to cultivate the original mycelium (also called secondary mycelium), which involves inoculating the hyphae of the mother mycelium into sawdust or grain-based substrates to expand and propagate it into the original mycelium. The third step is to cultivate the planting mycelium (also called tertiary mycelium or production mycelium), which uses the hyphae of the original mycelium to further expand propagation once more, resulting in the planting mycelium that can be directly used in production. After the continuous expansion from mother mycelium → original mycelium → planting mycelium, the quantity of edible fungus mycelium increases significantly. Meanwhile, the mycelium also becomes thicker.