Bio

Kumatarō Kido was born around 1857 in Japan. By the 1890s, he had been involved in a common-law marriage with a woman whose name was not preserved in public records. However, this relationship ended in personal betrayal and violence. Kido’s partner left him for another man, a rival named Torajirō Matsunaga, which reportedly became a significant emotional catalyst for the subsequent crimes.

Following the breakup, Kido became further entangled in a personal feud with the Matsunaga family. According to surviving records, Torajirō’s brother, Denjirō Matsunaga, had assaulted Kido and fraudulently taken part of his money. These grievances, both romantic and financial, appear to have fueled Kido’s escalating anger and led to the planning of a mass revenge attack.

Kido sought assistance from his pupil, a younger man named Yagorō Tani, and together they devised a plan to eliminate the entire Matsunaga family, including Kido’s former partner and her relatives. The pair armed themselves with hunting guns and traditional Japanese swords, carefully planning a sequence of violent attacks. Despite the personal nature of the dispute, the resulting massacre would include eleven deaths, among them children and an infant.

Murder Story

On 25 May 1893, Kido and his accomplice Yagorō Tani carried out one of the most infamous spree killings in Meiji-era Japan. The incident became known as Kawachi Jūningiri (河内十人斬り), which translates to “The Kawachi Ten-Slaying” — though the final death toll reached eleven.

The attacks began at the residence of Denjirō Matsunaga, the man Kido held responsible for his financial and personal ruin. At this location, four individuals were killed, including members of Denjirō’s household.

The killers then moved to the home of Denjirō’s son, where they murdered five more people. Among the victims were both adults and children.

Finally, Kido and Tani tracked down and killed Kido’s former common-law wife as well as her mother, completing their intended cycle of revenge. Notably, Torajirō Matsunaga, the original romantic rival, was not present at any of the attack sites and survived the massacre.

The killers then committed suicide, though their bodies were not discovered until 7 June 1893, over ten days later, indicating a secluded or forested location. The weapons used were believed to be traditional Japanese swords and firearms, prepared in advance for the killings.

Given that both Kido and Tani died at the scene, there was no criminal trial. The case nonetheless attracted national attention due to its personal motives, the scale of the violence, and the fact that the murders were carried out in a premodern village setting during a period of Japan’s modernization.

The emotional and financial motivations behind the massacre, coupled with the high number of victims — including women and children — led to widespread shock and condemnation in the press of the time.

In modern Japanese literature, the case has remained in cultural memory. Notably, punk rock singer and novelist Kō Machida wrote a fictionalized retelling titled “Kokuhaku”, inspired by the murders.

Kumatarō Kido is deceased, having died on the day of the killings. The case remains historically significant as one of Japan’s earliest recorded spree killings and is studied in criminology and cultural literature as a case of revenge-fueled mass murder in Meiji Japan.