Shimabara Rebellion

The largest internal conflict of Japan's Edo period broke out in December 1637 on the Shimabara Peninsula and the Amakusa Islands in western Kyushu. Peasants crushed by taxation and famine, joined by masterless samurai and many local Christians, rose against their lords and held out for months in the ruined Hara Castle before being overwhelmed in April 1638. The rebellion hardened the Tokugawa shogunate's ban on Christianity and its policy of national seclusion.

Shimabara had once belonged to the Arima, a Christian clan, and many of its people shared that faith. In 1614 the Arima were moved away and replaced by the Matsukura. The new lord, Matsukura Shigemasa, sought favour with the shogunate by funding costly projects, including work on Edo Castle and a new castle at Shimabara, and paid for them with crushing taxes while harshly persecuting Christians. His son Katsuie continued the same policies. On the nearby Amakusa Islands the Terasawa family behaved in much the same way. Unemployed samurai, former retainers of extinct or displaced clans, added to the unrest.

Conspirators met in secret, and on 17 December 1637 the rebellion began with the killing of a local magistrate. Amakusa Shirō, a charismatic youth of about sixteen, emerged as its leader. The rebels attacked the Terasawa castles at Tomioka and Hondo, then Shimabara Castle, but were driven off by troops from neighbouring domains. They then fortified the ruins of Hara Castle, the old Arima seat, using timber from their boats and supplies seized from Matsukura storehouses.

The shogunate, under the shogun Tokugawa Iemitsu, gathered a large army drawn mainly from the domains of Kyushu. Its size is variously estimated, with figures of 100,000 to 200,000 given, and around 125,000 often cited. The famous swordsman Miyamoto Musashi served as an adviser and was reportedly knocked from his horse by a stone. At the shogunate's request the Dutch trading post at Hirado supplied gunpowder and cannon, and the Dutch ship de Ryp bombarded the fortress, without much effect; it was withdrawn after the rebels mocked the besiegers for relying on foreigners.

The first commander, Itakura Shigemasa, was killed in a failed assault, and Matsudaira Nobutsuna replaced him. The defenders, perhaps 20,000 to 37,000 strong, resisted through the winter, but with no supply lines their food and ammunition ran low. A desperate sortie on 4 April 1638 failed, and deserters revealed how weak the garrison had become. Shogunate troops stormed the outer defences on 12 April, and resistance ended on 15 April.

An estimated 37,000 rebels and sympathisers were executed. Amakusa Shirō's head was displayed in Nagasaki, and the castle was burned and buried with the dead. Matsukura Katsuie was found guilty of misrule and beheaded in Edo, the only daimyo to suffer that fate in the Edo period, while Terasawa Katataka was stripped of his Amakusa lands. Settlers from elsewhere in Japan were brought in to farm the depopulated peninsula, and every inhabitant had to register with a Buddhist temple.

Although the rebellion is often remembered as a Christian uprising, scholars generally see peasant anger at misgovernment as its main cause. Suspecting European Catholic involvement, the shogunate expelled the Portuguese traders and tightened seclusion by 1639, and Christianity survived only in secret. It was the last large-scale fighting in Japan until the Boshin War at the close of the Tokugawa era.

Our 1650 map shows Japan under the Tokugawa shogunate shortly after the rebellion was crushed.