Diyu is the Chinese underworld, a layered and, in most developed accounts, explicitly bureaucratic realm administered by a hierarchy of courts and judges through which every soul must pass after death, reflecting a broader Chinese cultural habit of imagining the unseen world as organised along the same administrative lines as the imperial state itself. The concept synthesises indigenous Chinese ideas about the dead and the underworld, older terms such as Huangquan and Fengdu, with Buddhist cosmology imported from India, particularly the ten courts and their judges, resulting in a distinctly Chinese hybrid rather than a straightforward import of either Indian Naraka or any single native precursor.
James Watson and Evelyn Rawski's study of Chinese death ritual notes that Diyu's bureaucratic imagery is not merely decorative but functionally connects the underworld directly to actual Chinese funerary and memorial practice, since paper money, paper houses, and other burnt offerings sent to the dead are explicitly understood as payments or resources meant to help a soul navigate Diyu's courts, bribe or satisfy its officials, and eventually secure a favourable rebirth, making the realm's administrative character a live, practically consequential belief rather than only a cosmological curiosity.