This project investigates the impact of medical and religious concepts and theories on the formation of knowledge about human organs and gendered health in premodern Japan. Its aim is to write cultural histories of the five viscera, pregnancy, and childbirth as seen through the Buddhist, medical, and prognostication manuscripts from Japanese archives. This project thus analyses the primary source materials that were previously not considered significant by the historians of Japan or East Asia who so far tended to privilege classical Chinese medical sources. It rectifies this problem by considering the premodern Japanese text corpora against the background of transcultural flows of Buddhist and medical knowledge on men’s and women’s health from premodern India, China, and Korea that brought with them Buddhist scriptures and medical texts as well as ritual technologies focusing on illness, risk control, divination, longevity, and talisman writing.