The Chinese seventh lunar month carries two distinct religious explanations for the same public observance, and Chinese practice has never required choosing between them. In the Daoist reading, Zhongyuan, the fifteenth day is one of three assize days of the underworld bureaucracy, when the gates of the lower world open and its officials review and release spirits, including those with no living descendants to tend them, so the public offerings feed a population the ordinary ancestral cult does not reach.
The Buddhist reading, Yulanpen, ties the same date to the story of Mulian, a monk whose mother had been reborn among the hungry ghosts as punishment for her greed in life, and whom Mulian frees only by making offerings to the whole assembled monastic community on this day, a story that gave rise to the wider practice of feeding hungry ghosts as an act of merit transferable to the dead. Both explanations account for the same visible acts, food left at roadsides, paper money burned, empty front row seats at street opera, and ordinary households and temple communities alike draw on whichever framing suits their own religious affiliation, or simply both at once.
Buddhist temples across East and Southeast Asia mark the day under variant names carrying the same Yulanpen root, including Obon in Japan, whose midsummer welcome of ancestral spirits shares a common origin with the Chinese observance even though the two calendars and surrounding customs have diverged considerably over the centuries since.