The so-called Qi Refinement is refining and incorporating a strand of pure innate spiritual energy into oneself, and the success defines the entrance into the Qi Refinement Realm.
This process has no real bottleneck; the only difficulty is... finding a strand of innate spiritual energy that matches the attribute of one's own cultivation technique.
"This is a strand of innate Green Wood spiritual energy, Xiaobai, you refine it."
Yang Shi had gone to the Xuan Stone Sect last year and spent 800 spirit stones to purchase this wood attribute innate spiritual energy for Jiang Xiaobai.
"Okay!"
Jiang Xiaobai channeled her Qi to extract the innate Green Wood spiritual energy from a small bottle and introduce it into her body.
The exceedingly pure innate spiritual energy instantly swept up all the spiritual energy stored in her dantian as if a high-ranking entity commandeering all ordinary spiritual energies.