Koka Ninja in the Edo Period
Tokugawa Ieyasu unified Japan and established the Edo shogunate in 1603, ushering in a period of peace that lasted more than 260 years.
The Shimabara Rebellion
The Shimabara Rebellion of 1637–1638 was the last major battle in which Koka ninja played a role. Christianity, which had entered Japan in the sixteenth century, was suppressed by the shogunate. The anti-Christian policies of the shogunate prompted Amakusa Shiro (1621–1638), a young Japanese Christian, to lead an uprising in present-day Nagasaki and Kumamoto Prefectures. Shiro and his forces established their stronghold in Hara Castle, an abandoned structure in the southern part of Nagasaki Prefecture.
Ten Koka ninja were among the forces sent to stop the rebellion in 1638, and their task was to collect information from within Hara Castle. They successfully infiltrated the castle and sabotaged the rebels’ food supply; however, confused by the unfamiliar local dialect, they were caught by the rebels before they could escape.
The Koka Koshi
Following the unification of the country under the Tokugawa shogunate in 1603, the ninja faced a general decline in demand for their services, with some families even experiencing poverty.
In 1789, a group called the Koka Koshi (Koka veteran warriors) journeyed to Edo, presenting the Bansenshukai (a compilation of detailed ninja knowledge) to the shogunate with the aim of proving their heritage and professionalism. For their efforts, they received silver to take back to the other ninja families in Koka.
