Kirishitan (吉利支丹, 切支丹) meant Christian(s) in Japanese and is today used as a historiographic term for Christians in Japan in the 16th and 17th centuries.

The missionary activities of Catholicism in Japan were started in 1549 and exclusively performed by Portugal-sponsored Jesuits until Spain-sponsored orders gained access to Japan.

The activities of Roman Catholicism were sponsored by the kingdoms of Portugal and Spain. Proselytizing was an integral part of expanding their territories or influence. By the permission of the Pope, they divided the non-Christian world between themselves.

Portugal and Spain disputed about the who got to exploit Japan Portugal and Spain disputed about the who got to exploit Japan. Since neither could colonize it, the exclusive right to spread Christianity in Japan meant the exclusive right to trade with Japan. Portugal-sponsored Jesuits took a lead in proselytizing in Japan over Spaniards.

This recognition of reality was approved by Pope Gregory XIII's papal bull of 1575, which decided that Japan belonged to the Portuguese diocese of Macao (across the bay from Hong Kong).

In 1588 the diocese of Funai (Nagasaki) was founded under the protection of the Portuguese king. Thus the Portuguese saw Japan as a "province that belonged to the conquest of the Portuguese."

In rivalry with Jesuits, Spain-sponsored Christian orders sneaked into Japan via Manila. While criticizing Jesuit activities, they actively lobbied the Pope. Their campaigns resulted in Pope Clement VIII's decree of 1600 that allowed Spanish friars to enter Japan via the Portuguese Indies, and Pope Paul V's decree of 1608 that abolished the restrictions on the route.

The Portuguese accused Spanish Jesuits of working for their homeland instead of Christ. The power struggle between Jesuits and the other religious orders caused a schism within the diocese of Funai.

The Roman Catholic world order was challenged by the Netherlands and England. This furthered divided the Christians, since these two countries were officially Protestant.

Japan built trade relations with the Netherlands and England Japan built trade relations with the Netherlands and England. Although England withdrew from the operations in ten years due to lack of profitability, the Netherlands continued to trade with Japan and became the only European country that maintained trade relations with Japan until the 19th century.

Jesuits believed that it was very effective to seek to influence people in power and thereby force the religion down the throats of the commoners. It is confirmed that as feudal lords converted to Catholicism, the number of believers in their territories was drastically increased.

Historians presume forced conversion of the commoners although Christians would claim that massive conversion resulted from influence of their lords' "exemplary behavior", not from forced conversion. The degree of their religious sincerity became clear when their rulers gave up the religion or were overthrown and the vast number of Christians deserted the churches.

The Jesuits in Japan had to maintain economic self-sufficiency because they could not expect stable and sufficient payment from their patron, the King of Portugal. Alternatively, the king allowed Jesuits to engage in Portuguese trade with Japan.

Such economic activity can be found in Francis Xavier, the pioneer of Catholic missions in Japan. He covered the cost of missionary work by selling pepper obtained in Malacca. From 1550s to 70s, Jesuits covered all necessary expense with trade profits and bought land in India.

The Jesuits’ officially recognized commercial activity was a fixed-amount entry into the Portuguese silk trade between Macau and Nagasaki. They financed to a certain amount a trade association of Macau which purchased raw silk in Canton and sold it in Nagasaki, the center of Christianity in Japan.

The Jesuits did not confine their commercial activity to the official one but expanded into unauthorized markets. For the Macau-Nagasaki trade, they dealt silk fabrics, gold, musk and other goods. In other words, they became smugglers.

It was mainly procurators who brokered Portuguese trade It was mainly procurators who brokered Portuguese trade. They resided in Macau and Nagasaki, and sold to Japanese customers such as the shogunate. Jesuits could expect not only rebates but also favorable treatments from the authorities. For this reason procurator became an important post amongst Jesuits in Japan.

At the same time, Portuguese merchants required procurators who were familiar with Japanese customs as they established no permanent trading post in Japan. Probably the most notable procurator was Joao Rodrigues, who even participated in the administration of Nagasaki.

Missionaries were not reluctant to take a military action if they considered it an effective way to Christianize Japan. They often associated military action against Japan with the conquest of China. They thought that well-trained Japanese soldiers who had experienced long civil wars would help western countries conquer China.

For example, the Jesuit procurator Alessandro Valignano persuaded Philippine Governor that it was impossible to conquer Japan because the Japanese were very brave and always received military training but that Japan would benefit them when they would conquer China.

Francisco Cabral also reported to the King of Spain that priests were able to send to China two or three thousand Japanese Christian soldiers who were brave and were expected to serve the king with little pay.

The Jesuits provided various kinds of support including military support to Kirishitan daimyo when they were threatened by non-Kirishitan daimyo.

When the shogun issued the first ban on Catholicism in 1587, the Jesuits in Japan planned armed resistance. At first they sought help from Kirishitan daimyo but the daimyo refused. Then they called for a deployment of reinforcements from their homeland and colonies.

But this plan was abolished by Valignano But this plan was abolished by Valignano. Like Kirishitan daimyo, he realized that a military campaign against the powerful ruler would bring catastrophe to Catholicism in Japan. In 1590 the Jesuits decided to stop intervening in struggles between daimyo, and to disarm themselves.

It seems that the Jesuits had no military plan during the Edo period since they realized that the Tokugawa shogunate was much stronger and more stable than the previous administration. In contrast, other Christian orders relatively openly discussed military options. In 1615 a Franciscan emissary of the Viceroy of New Spain asked the shogun for land to build a Spanish fortress and deepened Japan's suspicion against Catholicism.

When the Jesuit priest Francis Xavier arrived, Japan was experiencing a nationwide civil war. Neither the emperor nor the Ashikaga shogun could exercise power over the nation.

At first Xavier planned to gain permission for building a mission from the emperor but was disappointed with the devastation of the imperial residence. The Jesuits approached daimyo in southwestern Japan and succeeded in converting some of these daimyo.

In 1587 the shogun banned the ruling class from converting to Catholicism as he was concerned that forced conversion by them made peasants dangerous rebels like the ikko ikki sect of earlier years. At the same time he put Nagasaki under his direct control to control Portuguese trade. In 1597, 26 Kirishitan followers were executed in Nagasaki at Hideyoshi's order.

The Tokugawa shogunate finally decided to ban Catholicism in 1612 The Tokugawa shogunate finally decided to ban Catholicism in 1612. This marked the end of open Christianity in Japan. The immediate cause of the prohibition was a case of fraud but there were also other reasons behind it. The shogunate was concerned about possible invasion by Iberian colonial powers, as had happened in China.

Non-religious researchers find it difficult to treat martyrdom as history. Instead of giving detailed accounts, they just point out the rate of martyrdoms; there were a thousand martyrs at most whereas the number of Christians at their peak is estimated at 500 thousand. In contrast, Christians attach a great importance to martyrdom probably due to the nature of Christianity.

The Japanese government used Fumie to identify Catholics The Japanese government used Fumie to identify Catholics. Fumie were pictures of the Virgin Mary and Christ and the government officials made everybody trample on these pictures. People reluctant to step on the pictures were identified as Catholics and were sent to Nagasaki.

The policy of Edo was to turn them from their faith The policy of Edo was to turn them from their faith. However, if the Catholics refused to change their religion, they were tortured.

But as many of them still refused to abandon their faith, they were killed by the government. Execution took place at Nagasaki's Mount Unzen where many were dumped into the volcano.

The Shimabara Rebellion, led by a young Christian boy named Amakusa Shiro Tokisada took place in 1637. About 27,000 people joined the rebellion, but it was crushed by the shogunate. They are not considered martyrs since they organized armed resistance.