The custom of Wang Yeh boat worshiping, is one of the most unique folk beliefs in southern China and Taiwan. It's a ritual for expelling plagues and death. Given the high humidity and temperatures, southern China used to be the epicenter of diseases and was regarded as a plague rampant region. Due to underdeveloped medical knowledge, people didn't know the cause or how to treat patients; fear toward unknown epidemics was then left for the spiritual realm to deal with by worship. After worshiping the spirits that spread plagues, the spirits were invited on board a boat made out of paper and sent out to sea which symbolizes sending the plague and evil away to bring health and peace back to the local residents. The wind and sea currents drifted the boats of 'evil' circulating around
southern China, Taiwan and Penghu. Anywhere one of these boats might drift into , residents would have to pick up the boat and 'treat' the evil spirits before building a boat and sending them on their way.
Over time, with the improvement of sanitary conditions, the progress of medication and the development of civilization, plagues were no
longer rampant in the area and the spirits of plagues were transformed into deities of plague, also known as Wang Yeh, who inspect the good and evil of people and punished the bad by spreading pestilence. These inspections are known as 'inspections on behalf of heaven' (代天巡狩 daitian xunshou)
and the meaning of building a boat was changed from expelling plague and death to sending the deities back to heaven from their inspections on behalf of heaven, hopefully taking disease and calamity with them. The practice was evolved from "sending the boat to an open sea and drift it away" to "set fire to the boat and rise with ashes to heaven".
