The 1st of September 2023 marked the 100th anniversary of the Great Kantō Earthquake.

The Great Kantō Earthquake (関東大地震 Kantō daijishin) was a massive tremor that hit Tōkyō and the surrounding prefectures on 1 September 1923. The Japanese term Kantō daishinsai (関東大震災) also refers to the damage that ensued in the following days. The earthquake struck at 11:58 AM with a violent uplift of the land in the prefectures of Tōkyō, Kanagawa, Chiba, Saitama, Ibaraki , Yamanashi , and Shizuoka. Damages were also reported in Nagano , Gunma, and Tochigi prefectures.

Great Kanto Earthquake Nihonbashi

Nihonbashi after the Great Kanto Earthquake. The Mitsukoshi Main Building is visible on the left side of the bridge.

According to the Meteorological Agency of Japan, the quake was 7.9 on the Richter scale. It was followed by another severe tremor 24 hours later and several hundred minor tremors that caused little or no damage but kept the population in fear and agitation. The earthquake damaged many buildings and killed or injured many people outright. Fire, however, caused more destruction than the tremor itself. Many people had begun charcoal or wood fires to prepare their lunch. The initial shock scattered burning embers, starting numerous fires that could not be extinguished. In Tōkyō and Yokohama, the nation's largest port, these fires spread rapidly and consumed large areas of the downtown sections. A tsunami that reached up to 10 metres high struck the coast of Sagami Bay, Bōsō Peninsula, Izu Islands, and the east coast of Izu Peninsula within minutes, causing many deaths, including about 100 people along Yuigahama Beach in Kamakura and some 50 people on the Enoshima causeway.

Yokohama Kanto Earthquake

Yokohama in early September 1923 (Robert Neff Collection)

Although official statistics were not verifiable and entirely reliable, they reveal the disaster's extent: 104,619 people were reported dead or missing, and 52,074 were injured. Ninety-one thousand nine hundred ninety-five were from the urban areas of Tōkyō and Yokohama, and only 12,624 were from rural areas, where conflagration was not a severe problem. According to the statistics, the area's total population was about 11,758,000; some 3,248,205 people had their homes damaged or destroyed. In metropolitan Tōkyō, where 2,265,000 people lived, 1,604,321 (70.85%) lost their homes.

The figures for Yokohama were 442,600 and 378,704 (85.56%), respectively. The statistics also show that 30.37% of all homes in the Kantō region were at least heavily damaged and that 20.39% were destroyed. In Tōkyō, 73.39% of the houses were damaged, and 63.18% were destroyed (only 0.88% by the tremor and the rest by fire). In Yokohama, near the epicentre, 95.03% were damaged, and 72.53% were destroyed (9.82% knocked down). Fires caused most of the damage, destroying 16.66% of all the houses in the seven prefectures affected, but 62.3% of the homes in Tōkyō and 62.71% in Yokohama.

Ryōunkaku (凌雲閣)

The Ryōunkaku (凌雲閣), a 50-metre-tall brick tower in Asakusa built in 1890, partly collapsed.

Estimates of property damage range from 500 million yen to 10 billion yen, whereas the official statistics amount to some 5.5 billion yen (by comparison, the Japanese GDP in 1922 amounted to some 15 billion yen). Insurance policies generally excluded earthquake damage, but in 1924, the government arranged "sympathy payments" through insurance companies. However, only 100 million yen were ever paid, leaving public institutions and individuals alike to struggle with the aftermath.

Urban building techniques were also responsible for the extensive fire damage: Most homes, businesses, and public buildings were made of wood and other highly flammable materials. Additionally, exceptionally few open spaces might have acted as firebreaks. Buildings and streets were too congested to slow or stop the flames.

Fanned by steady breezes, the fires spread rapidly and developed into raging firestorms. Intensely heated air rose to a high altitude, creating a partial vacuum that drew fresh air into ground-level fires. The winds were estimated to reach 70-80 kilometres per hour. The firestorms produced cyclones or tornadoes, several of which occurred in downtown Tōkyō. The cyclones were particularly deadly, consisting of superheated air from which most oxygen had been burned. One cyclone passed over the vacant grounds of the Military Clothing Depot in Honjo (本所) in Sumida, where many had fled from the flames, suffocating some 40,000 people.

The earthquake destroyed municipal services and infrastructure. Water mains and fire hydrants were ruptured and unavailable for fire fighting. Telephone and telegraph lines were knocked out, and even radio communication with the rest of the country was difficult, forcing the government to rely on military planes and carrier pigeons. The government itself was in a state of disarray: Prime Minister Katō Tomosaburō (加藤 友三郎, 1861-1923) had died on 25 August, and on 2 September, a new cabinet under Yamamoto Gonnohyōe (山本 権兵衛, 1852-1933) was formed hastily and declared martial law as one of its first acts.

Kantō Massacre

In urban disaster areas, the order was further disrupted by rumours that Koreans were lighting fires and poisoning the few remaining wells. Police services were too much in disarray to intervene and control the populace. Vigilante groups were set up to protect neighbourhoods, killing 231 Koreans in the first week of September.

In the days that followed the earthquake, Japan, sensitive to world opinion, began censoring news reports of the disaster and the subsequent massacres. The Japanese premier issued a house-to-house appeal to the population to exert its characteristic self-control and insisted that peaceful Koreans had to be protected. By 7 September, thousands of Koreans had been rounded up and placed in internment camps for their own safety. Although many terrified Koreans sought the protection of the police and military, others were terrified of these figures of authority who, in some instances, actually took part in the atrocities. It is estimated that 6,000 - 10,000 Koreans and other nationals were killed before the authorities could reestablish control. Also murdered were some 700 Chinese, as well as Okinawans and even Japanese, who spoke regional dialects.

The military police (憲兵隊 Kempeitai) took advantage of the situation to liquidate workers and political dissidents after declaring martial law, and some 35,000 troops entered the disaster area. On 4 September, military police arrested and killed several unionists and four members of vigilante groups at the Kameido police station. On 16 September, military police arrested and killed the anarchist Ōsugi Sakae (大杉栄, 1885-1923), his wife Itō Noe (伊藤野枝, 1895-1923), and his six-year-old nephew.

Further vilifying the Koreans and giving justification for the massacre, Japanese-owned newspapers reported, "the activities of the Koreans led to the discovery of a plot to assassinate the prince regent, members of the imperial family and high officials." No one will probably ever know how many Koreans were killed in those terrible days following the earthquake. To this day, it remains a dark page in the annals of Korean-Japanese relations. While high-level involvement was never proven, the two incidents illustrate the breakdown of order among the authorities in the devastated capital region.




Ginza 4-chome

The destruction in Ginza 4-chome.

Downtown Yokohama

Downtown Yokohama burning.

Yokohama Specie Bank

Yokohama Specie Bank (present-day Kanagawa Prefectural Museum of Modern Art)

Tsurugaoka Hachimangu Shrine

Tsurugaoka Hachimangu Shrine in Kamakura

Great Buddha of Kamakura

The Great Buddha of Kamakura, weighing in at 120 tonnes, was moved some sixty centimetres.