Like the other East Asian countries discussed before, Korea's practice of ancestor worship is largely based off of Confucian teachings. In Korea, this practice is known as
jesa. Like the Chinese, Korea's practice of ancestor worship falls largely on the man of the family--the father is obligated to lead the worship of ancestors within the family, as is the first son of the family. Services to dead ancestors have been traditionally required eight times in the year, along with established holiday rituals.
Similar to the Chinese and Japanese, Koreans believe that there are multiple spirits and souls that reside within a person's body, however unlike the three spirits of Chinese practices, Koreans believe there are seven souls and three spirits. With death these spirits go to the afterlife, while one spirit remains within the body as well as the seven souls. Also similar to the Chinese, an ancestor or spirit table is utilized in worship.
Food offerings are often made, though placement of food and offerings is very specific within the ritual itself (I'm trying to find information on the specifics of this). Some families have altars and others do not. And while each family has their own small altar within the family unit, they typically will also have a much larger altar with all of the ancestors at the main family house (if they have a main family house). This connection to the main family is only broken after three generations when another "main family" can be created. Unlike my studies of other countries' ancestor rituals, however, Korea seems to be the only one which may utilize the help of a shaman in rituals of ancestor worship instead of solely relying on the men within the family.Such shamans are often utilized to cleanse a home following the death of a family member. In many ways, this purification of a home seems similar to the Catholic tradition of exorcism as it deals with purifying the home.
(1) Kwang Kyu Lee, "The Concept of Ancestors and Ancestor Worship in Korea",
Asian Folklore 43.2 (1984): 199-214.
(2) Kwang Kyu Lee, "Confucian Tradition in the Contemporary Korean Family" in
Confucianism and the Family: A Study of Indo-Tibetan Scholasticism, ed. Walter Slote and George De Vos (Albany: State University of New York, 1998), 249-267.