This Chapter details an alchemical process for achieving immortality. It describes the interplay of Yin and Yang energies within the body, mirroring cosmic cycles, and outlines a regimen of internal energy refinement through specific practices and seasonal timing. The process involves the symbolic union of internal energies, likened to a pregnancy, culminating in the creation of a "Golden Elixir." Success depends on precise timing, inner harmony, and dedicated practice over many years. The text provides analogies and instructions for practitioners at various stages of advancement.