Great Kanto Earthquake
On 1 September 1923, a powerful earthquake struck the Kanto plain of Japan, devastating Tokyo, Yokohama, and surrounding prefectures. Estimated at magnitude 7.9, it triggered fires, landslides, and a tsunami, and killed roughly 100,000 to 140,000 people, with the figure often given as around 105,000 in later studies. It remains one of the deadliest natural disasters in Japanese history, and it reshaped both the physical form of the capital and Japan's approach to disaster preparedness.
Japan sits at the junction of several tectonic plates, and earthquakes were a familiar hazard. Tokyo, the country's political and economic center, had grown rapidly since the Meiji Restoration, and much of its housing consisted of densely packed wooden buildings. Yokohama, the nation's leading international port, was similarly vulnerable. Few people expected a quake on this scale, and building standards, especially for ordinary homes, offered little protection against fire.
The shaking began just before noon, when many households were cooking lunch over open flames. The rupture occurred along the fault beneath Sagami Bay, and the tremors lasted several minutes. Buildings collapsed across Yokohama, and fires spread quickly through both cities. In Tokyo, the worst single tragedy occurred at an open area in the Honjo district, where tens of thousands of people who had fled with their belongings were caught by a fire whirl. Coastal towns were struck by waves, and landslides destroyed communities in the hills. Several million people were left homeless.
The disaster also had a dark social aftermath. Amid panic and rumors, vigilante groups, with some involvement by police and soldiers, attacked Koreans living in the region, falsely accused of poisoning wells and committing arson. Chinese residents and some Japanese were also killed. Estimates of the Korean death toll vary widely, from several hundred to several thousand, and the episode has long been a subject of historical debate and official reluctance to acknowledge it fully.
Reconstruction was led by Gotō Shinpei, who proposed an ambitious plan for rebuilding Tokyo with wider roads, parks, and modern infrastructure. Budget limits forced a scaled-down version, but it still left a lasting mark on the city's layout. The earthquake also advanced seismology and earthquake-resistant engineering in Japan. Each 1 September is now observed as Disaster Prevention Day, when drills and public education keep the memory of 1923 alive.