Tokyo Metropolitan Peace Day

What Is Tokyo Metropolitan Peace Day?

Every March 10th is "Tokyo Metropolitan Peace Day" (東京都平和の日, Tōkyō-to Heiwa no Hi) in Japan. The date commemorates March 10, 1945, when the Great Tokyo Air Raid (東京大空襲, Tōkyō Daikūshū) — the most destructive conventional bombing raid in history — killed an estimated 80,000–100,000 people in a single night, destroying approximately 40 square kilometers of eastern Tokyo. Tokyo Metropolitan Government designated March 10th as Peace Day in 1990 to commemorate the victims and to maintain awareness of the raid's devastating impact.

The Great Tokyo Air Raid of March 10, 1945

On the night of March 9-10, 1945, 334 U.S. B-29 Superfortress bombers flew low over eastern Tokyo — dropping approximately 1,700 tons of incendiary bombs (primarily M69 napalm cluster bombs) designed to ignite the densely packed wooden residential districts of working-class shitamachi neighborhoods. Fanned by strong winds, the resulting firestorm created an inferno that overwhelmed both firefighting capacity and civilian evacuation efforts. The Sumida, Arakawa, and Kōtō areas of eastern Tokyo were virtually incinerated in a few hours — the charred bodies of victims who had tried to shelter in the Sumida River were found floating in the river at dawn.

The Scale of Destruction

The March 10, 1945 raid killed more people in a single night than either atomic bomb — making it the single most deadly conventional bombing raid in history. The destruction of 40 square kilometers of Tokyo — approximately 267,000 buildings — left approximately 1 million people homeless in a single night. The raid was followed by continued firebombing of Tokyo and dozens of other Japanese cities through the spring and summer of 1945, cumulatively killing far more Japanese civilians than the atomic bombs.

Memory and Commemoration

The Tokyo Metropolitan Edo-Tokyo Museum maintains permanent exhibitions on the March 10 raid, and the Tokyo Air Raid Documentation Center (東京大空襲・戦災資料センター) preserves testimonies and documents from survivors. Peace Day observances include memorial ceremonies at the victims' cenotaph in Yokoami-chō Park, where approximately 100,000 victims' remains are interred.

Fun Facts

• Low-altitude tactics: General Curtis LeMay's decision to send the B-29s at low altitude (approximately 5,000-9,000 feet) at night — contrary to previous high-altitude daylight precision bombing doctrine — was justified by its devastating effectiveness. The low altitude and incendiary payload maximized the destructive effect against Tokyo's wooden residential construction.
• Yokoami-chō Park: The park where Tokyo's air raid victims are memorialized was also the site of the Great Kantō Earthquake's mass casualties in 1923 — making it a site of double commemoration for Tokyo's two greatest 20th-century disasters.