The Heian period was a time of many disasters, and the disasters had a great impact on politics. By knowing how many disasters occurred and when, the background of the belief in the ghost, the consequent concessions of the emperor, and why the common people tried to escape from the tax. ?? I think it will be a little closer. Of course, disasters aren't the whole reason.
For that reason, I will make a chronological table this time.
Heian period disaster chronology
Let's start with the disaster of the Emperor Kanmu that entered the Heian period.
The part surrounded by a square describes things that are thought to have been caused by a natural disaster, disaster countermeasures, and major incidents that occurred during the Emperor's dynasty.
■ Emperor Kanmu [781-806]
- 788 Eruption of Mt. Kirishima (near the border between Miyazaki and Kagoshima prefectures)
- 790:Smallpox epidemic in Kyoto and Kinai
- 792:Flood in Kochi
- 794:Flood in Kochi
- 798 Drought in Kagawa
- 799:Long rain in Kagawa and Ehime
- 800 years eruption of Mt. Fuji
| Moved from Heijokyo to Nagaokakyo in 784. One month before that, bandits continued to appear in Heijokyo. In 794, the capital was moved from Nagaokakyo to Heiankyo. It is said that the reason for this is the repeated floods and the tatari of Prince Sawara, the younger brother of Emperor Kanmu (because people close to him died one after another). It was also an era when Ezo was subdued in earnest. |
■ Emperor Heijo [806-809]
- 802:Wind and flood damage in Tokushima
- 805 Earthquake / Tsunami in Tokushima
- 806 Steam eruption of Mt. Bandai (Fukushima Prefecture) (it is unknown in what month)
- 807 Akita Yakeyama eruption?
| I love Fujiwara no Kusuko, who has her husband. Emperor Heizei himself was sick, so he was transferred in three years. |
■ Emperor Saga [809-823]
- 809 Drought in Kagawa
- 810-823:Steam eruption at Mt. Chokai (Akita / Yamagata)
- 810-824:It is estimated that the Kamogawa and Katsuno rivers were established in Kyoto (the government office for hydraulic control)
- 817:Great drought in Kagawa
- 818 flood in Kagawa
- August of the same year, M7.0-8.0 earthquake (=Hirohito's big earthquake) in the northern Kanto area
- 819 Drought over a wide area of western Japan
- 820:Is it a bad harvest?
↑ In May of the same year, "Kokushi / Gunji will accommodate the sick and will be treated with a regular tax"
There is a description that it is (from the Japanese history chronology)
| Kusuko Incident in 810 ← Power struggle between Mr. Fujiwara and the imperial family. In 819, he investigated the wealth of millionaires in Kinai and lent it to the needy. |
■ Emperor Junna [823-833]
- 826 or 827 Mt. Fuji eruption? (Details unknown)
- August 827 M6.5-7.0 earthquake in Kyoto (aftershock until June of the following year)
- 830:Water vapor eruption at Mt. Chokai (Akita / Yamagata). Mudflow also occurs.
- The same year, M7.0-7.5 earthquake in Akita
| In 827, the empty and devastated land in Kyoto was sold. |
■ Emperor Ninmyō [833-850]
- 837:Steam eruption at Mt. Naruko (Miyagi)
- 838:Medium-scale eruption on Izu Oshima
- 838-886 Large-scale magma eruption and water vapor eruption on Izu Oshima
- 841 Earthquake in Nagano before February 13
- The same year, an earthquake in Izu before May 3
- August 848:Kawayo Bridge, Uji Bridge, and Mamuta Embankment were damaged in Kyoto and Kinai due to the great flood.
- 850 M7.0 earthquake in Akita (date unknown)
Apart from the above disasters, it is said that famine, long rains, and plagues occurred frequently in Mutsu and Dewa provinces (Aomori, Akita, Yamagata, Iwate, Miyagi, Fukushima) from the beginning to the middle of the 9th century (Tohoku Heisei in the 800s). There is also a table showing the number of famines, so please check it).
| In 837, a search for bandits in Kyoto. In 842, Jōwa Incident. The first case of expulsion of another by Mr. Fujiwara. Mr. Ban, Mr. Tachibana, and the Fujiwara Shikike were hit hard, and Emperor Montoku, the son of Emperor Ninmy, took over. |
■ Emperor Montoku [850-858]
- 852 Drought in Kagawa
- 853 Smallpox epidemic in Kyoto, Kinai, and Kinai
- 854:A farmer in Mutsu is in need due to bad harvests
- 856 M6.0-6.5 earthquake occurred in Kyoto
- May 858 Flood in Kyoto
| In 852, the pond weir was repaired by the Kokushi and Gunji of each country, and agriculture was solicited. In 854, a soldier in Mutsu escaped and sent out 1000 soldiers to calm him down. In 857, he searched for a group thief in Kyo. In May 858, rice husks and salt from the Kokukurain were given to the poor in Kyoto. |
The pond weir is a reservoir and is often made on the Seto Inland Sea side of the Kinki, Sanyo, and Shikoku regions where there is little rain.
It is noteworthy that in 857 there was a “group thief” instead of a bandit in Kyo.
There have been bandits in Kyo so far, and probably bandits have appeared even after the disaster before 857. However, it is probable that the fact was not mentioned so much in the major books about the outbreak of bandits before 857 (of course, it may not be enough to find it, but at least it is written in the Japanese history chronology. If the outbreak of bandits was between the early Heian period and 857, only the description of the outbreak of bandits in 837 can be found).
Isn't the centripetal force of the imperial court gradually declining from this time due to repeated disasters and political corruption? You can also guess.
■ Emperor Seiwa [858-876]
- 859-877 Floods, droughts, winds, and plagues occur frequently nationwide
- 860 Earthquake, cold damage, snow damage in Kyoto (from Kyoto Historical Disaster Research)
- 861 Flood in Kochi
- Spring 863:Cough (influenza) epidemic in Kyoto and Kinai
- July of the same year, earthquakes, landslides, etc. in Echigo / Echigo (Toyama / Niigata)
- May 864-Mt. Fuji large-scale eruption
- November of the same year, eruption of Mt. Aso (Kumamoto)
- 866:Drought, storm and flood damage, floods in western Japan
- 867 eruption of Mt. Aso (Kumamoto)
- The same year, a steam eruption of Mt. Tsurumidake and Mt. Garai (Oita)
- 868 Earthquake at Harima / Yamashiro (Hyogo / Kyoto)
- 869 M8.3 Jogan earthquake (off Sanriku). A tsunami also occurred.
- 870 Eruption of Mt. Fuji? ??
- 871 Medium-scale water vapor eruption of Mt. Chokai (Akita / Yamagata) ➡ To magma eruption
- August of the same year:Flood in Kyoto (Is the Kamo River flooded?)
- March 874:Large-scale eruption and mudflow at Kaimondake (Kagoshima)
- August of the same year, a storm in Kyoto
- 875 Fumarole at Mt. Fuji
| In March 861, it was forbidden to send horses out of Mutsu and Dewa. In November, Kebiishi was not used for each group in Musashi Province. In May 862, ordered pirates to be added to Sanyo Expressway and Nankaido countries. In July 865, ordered pirates to be added to Sanyo Expressway and Nankaido countries. In April 866, punish the Kokushi who did not pursue the pirates. In July, a struggle over the excavation of the Hirono estuary, the gunji of Owari and Mino (western Aichi and southern Gifu). In September, the Otenmon Incident (Mr. Fujiwara's exclusion of others, Mr. Ban's fall). In March 867, one guardian was placed in every five houses to relieve pirates, and a detective (like a lookout) was placed on the main road. In November, Iyo Kuni Miyazaki Village was ordered to supplement the pirates. |
In the era of Emperor Seiwa, pirates frequently occur in the Seto Inland Sea. The reason why this piracy started was also the opposition to the Kokushi, who is cracking down on the harshness. The "Prohibition of Horses" decree in March 861 is still a measure to keep Tohoku's dissatisfaction from going out (an article about Ezo who was in Tohoku and Ezo and Fushū who returned to the imperial court. Ezo seems to have had a very close relationship with horses).
Summary
Looking at the whole, natural disasters in Tohoku, the Seto Inland Sea, and Kyushu stand out. In the early Heian period, volcanic eruptions in the Tohoku region occurred frequently, and the Seto Inland Sea was calm for a while, but basically droughts and floods. This seems to be largely affected by global warming. Furthermore, it is an eruption in Kyushu. You can see that the earthquake also entered the active period in the 9th century.
How many earthquakes are there in the 9th century? The wiki is easy to understand in one shot. Chronology of Earthquakes (Japan) – You can easily see the difference between the 8th and 10th centuries by looking at Wikipedia.
In addition to these natural disasters, fires are also included in the disasters, but since there are quite a few in Kyo alone, we will omit them. Regarding the fire, it seems that there was not only a misfire but also a power struggle.