Did you know that the underworld presented in Journey to the West is actually an amalgam of native Chinese and foreign Hindu-Buddhist beliefs? As far back as the Han Dynasty (206 BCE–220 CE), hell was considered an otherworldly bureaucracy where souls were kept en masse. With the coming of Buddhism from India, a different view of the underworld evolved wherein souls would be reborn in one of six paths (deva, asura, human, animal, hungry ghost, and hell) and burn off any bad karma via suffering in life until they were pure enough to be reborn in a Buddha realm. But starting around the 7th-century, the idea of purgatory appeared and brought with it the concept of the Ten Judges or Kings (shi wang, 十王). This is where the two previous views were combined. Souls would be brought before a magistrate and suffer punishment for a given sin before being sent onto the next court and so forth. After suffering for a three year period, the soul would finally be sent onto their next life (Teiser, 2003, pp. 4-7).
Two of the Ten Judges stand as perfect examples of the intermixing of the two belief systems. The seventh judge, King of Mount Tai (Taishan Wang, 泰山王), is an allusion to a famous Chinese holy mountain. The fifth judge, King Yama (Yanluo Wang, 閻羅王), is a Buddhist holdover from Hinduism who originally ruled as the god of the underworld (Teiser, 2003, pp. 2-3).
Not everyone living in medieval China could read Buddhist scriptures, so the purgatories were eventually illustrated as a powerful teaching tool. Nothing says behave like seeing a demon eviscerating someone in full bloody color. Such “Hell Scrolls” (Diyu tu, 地獄圖) remain quite popular even to this day. Charles D. Orzech (1994) suggests that one of the reasons why they remained popular through the end of dynastic China was because they served as not so subtle reminders to be a law abiding citizen. Otherworldly judges doling out painful punishments mirrored the actions of their earthbound counterparts. Real-world magistrates were known for using torture to gain confessions. One such device was used to slowly fracture the ankles and shins.
Those interested can see full color versions of hell scrolls here:
http://people.reed.edu/~brashiek/scrolls/index.html
Sources:
Orzech, C. D. (1994). Mechanisms of Violent Retribution in Chinese Hell Narratives. Journal of Violence, Mimesis, and Culture, 1. Retrieved from
https://www.uibk.ac.at/theol/cover/c…n01_orzech.pdf
Teiser, S. F. (2003). The scripture on the ten kings and the making of purgatory in medieval Chinese Buddhism. Honolulu, HI: University of Hawaii Press.