Cover image: “Shimabara Jinzu Gobyobu (Battle)” Asakura City Designated Cultural Property 1837, by Saito Shuho (Collection of Asakura City Akizuki Museum). The central part of Hara Castle where the “Shimabara Amakusa Uprising” took place. The 10th lord of the Akizuki Domain, Nagamoto Kuroda, (tasked Saito Shuho) made a pair of six-panel folding screens to commemorate the 200th anniversary of the suppression of the Shimabara-Amakusa Rebellion and to honor the longevity of the first lord of the domain, February 1638. This is a “battle map” depicting the all-out attack on Hara Castle on the 27th and 28th (there is also a “departure map”). The content is based on records such as the Shimabara Ikki Statement, and is known as a masterpiece of battle maps.

The Shimabara-Amakusa Rebellion of 1637–1638 stands as one of the most significant uprisings of early modern Japan, both in scale and consequence. It erupted during the Tokugawa shogunate in response to a combination of severe economic hardship and religious persecution. The immediate trigger was the policy of Matsukura Katsuie, the local lord of the Shimabara Peninsula Masuda Shirō Tokisada, also known as Amakusa Shirō, who imposed exorbitant taxes to fund ambitious construction projects. This economic strain, coupled with the national prohibition of Christianity—a religion concentrated most densely in this region—generated widespread discontent and ultimately ignited a rebellion.

Leadership of the revolt coalesced around a remarkable 16-year-old figure, whose charisma and organizational skill enabled the insurgents to assemble a considerable force. Initial estimates suggest that by the outset of the rebellion on December 17, 1637, the number of participants ranged from approximately 35,000 to 40,000. The composition of the rebel force was largely peasant, but it also included a contingent of warriors and ronin, or masterless samurai, drawn to the cause. While religious motives were not the sole impetus, the overwhelming majority of the rebels were Catholic Christians, who perceived the enforcement of anti-Christian edicts as a direct threat to their faith.

The rebels initially attempted to seize nearby castles but were unsuccessful. Recognizing the mobilization of a substantial shogunate force from surrounding provinces, they fortified themselves in Hara Castle. This stronghold had historical significance, as it belonged to the Arima family—Christian samurai who had previously lost favor with the shogunate.

By April 1638, shogunate forces had assembled an estimated 125,000 troops to besiege Hara Castle. The attackers also benefited from Dutch assistance, including artillery, gunpowder, and a warship. Despite the overwhelming numerical disadvantage, the defenders held out for several months, inflicting significant casualties on the besiegers amid harsh winter conditions. Ultimately, sustained attrition and the continuous arrival of shogunate reinforcements led to the fall of Hara Castle on April 15, 1638.

The aftermath was catastrophic for the rebels. Historical accounts indicate that roughly 37,000 defenders were executed, primarily by beheading, while the shogunate recorded approximately 10,000 casualties among its own forces. Hara Castle itself was destroyed and burned, leaving a landscape marked by mass death and ruin.

The rebellion had far-reaching consequences beyond its immediate military outcomes. The Tokugawa shogunate interpreted the uprising as confirmation of Christianity’s destabilizing potential, subsequently enforcing a comprehensive ban on the religion. Japanese Christians were compelled to practice clandestinely as “crypto-Christians,” and those discovered were executed. When the ban was lifted in 1873, following the Meiji Restoration and the return of imperial authority, around 30,000 Japanese emerged as former crypto-Christians—individuals who had secretly maintained their faith for centuries, albeit in a form substantially transformed from the original Catholic practices introduced in the 15th century.

The Shimabara-Amakusa Rebellion thus left an enduring imprint on Japanese religious and social history. Even today, Christianity remains a minor faith, followed by roughly 1% of the population, reflecting the profound and lasting impact of Tokugawa policies and the rebellion’s suppression.