Nagasaki Prefecture is a prefecture of Japan located on the island of Kyūshū. The capital is the city of Nagasaki. Nagasaki Prefecture, a unification of former provinces of Hizen, Tsushima, and Iki, has had close ties with foreign civilization for centuries. Facing China and Korea, the region around Hirado was a traditional center for traders and pirates. During the 16th century, Catholic missionaries and traders from Portugal arrived and became active in Hirado and Nagasaki, which became a major center for foreign traders. After being given free rein in Oda Nobunaga's period, the missionaries were forced out little by little, until finally, in the Tokugawa era, Christianity was banned under the Sakoku policy. After the prohibition of Christianity in the Edo period, foreign trade was restricted to Chinese and Dutch traders in Nagasaki, Dejima, but Kirishitan (Japanese Christian) worship continued underground. These Kakure Kirishitan (hidden Christians) were tried at every step, forced to step on fumi-e ("trample pictures", images of the Holy Mother Mary and saints) to prove that they were non-Christian. And with the banishment of all Catholic missionaries, traders from Catholic countries were also forced out of the country. Along with them, their children, half Japanese and half European, were also forced to leave the country. The majority was sent to Jagatara (Jakarta) and are still remembered by the locals as the people who wrote the poignant letters which were smuggled across the sea to their homeland. Today, Nagasaki has a prominent Chinatown and Catholic churches.