Task: Question Answering
Input (English): Passage: Japan has full religious freedom based on Article 20 of its Constitution. Upper estimates suggest that 84–96 percent of the Japanese population subscribe to Shinto as its indigenous religion (50% to 80% of which considering degrees of syncretism with Buddhism, shinbutsu-shūgō). However, these estimates are based on people affiliated with a temple, rather than the number of true believers. The number of Shinto shrines in Japan is estimated to be around 100,000. Other studies have suggested that only 30 percent of the population identify themselves as belonging to a religion. According to Edwin Reischauer and Marius Jansen, some 70–80% of the Japanese do not consider themselves believers in any religion. Nevertheless, the level of participation remains high, especially during festivals and occasions such as the first shrine visit of the New Year. Taoism and Confucianism from China have also influenced Japanese beliefs and customs. Japanese streets are decorated on Tanabata, Obon and Christmas.
Shinto is the largest religion in Japan, practiced by nearly 80% of the population, yet only a small percentage of these identify themselves as "Shintoists" in surveys. This is due to the fact that "Shinto" has different meanings in Japan: most of the Japanese attend Shinto shrines and beseech kami without belonging to Shinto organisations, and since there are no formal rituals to become a member of folk Shinto, Shinto membership is often estimated counting those who join organised Shinto sects. Shinto has 100,000 shrines and 78,890 priests in the country. Buddhism first arrived in Japan in the 6th century; it was introduced in the year 538 or 552 from the kingdom of Baekje in Korea.Christianity was first introduced into Japan by Jesuit missions starting in 1549. Today, fewer than 1% to 2.3% are Christians, most of them living in the western part of the country, where the missionaries' activities were greatest during the 16th century. Nagasaki Prefecture has the highest percentage of Christians: about 5.1% in 1996. As of 2007, there are 32,036 Christian priests and pastors in Japan. Throughout the latest century, some Western customs originally related to Christianity (including Western style weddings, Valentine's Day and Christmas) have become popular as secular customs among many Japanese.Islam in Japan is estimated to constitute, about 80–90%, of foreign born migrants and their children, primarily from Indonesia, Pakistan, Bangladesh, and Iran. Much of the ethnic Japanese Muslims are those who convert upon marrying immigrant Muslims. The Pew Research Center estimated that there were 185,000 Muslims in Japan in 2010.Other minority religions include Hinduism, Sikhism and Judaism, Bahá'í Faith, and since the mid-19th century numerous new religious movements have emerged in Japan. 
Question: what religion was introduced to Japan in the year 538 or 552?
Output (English): Buddhism.