Emperor Kanmu's two major projects are the relocation to Nagaokakyo and Heiankyo and the settlement of the Tohoku region.
This time, I will focus on the Tohoku region.
History of the Tohoku region
First, let's take a look at the situation in the Tohoku region at that time.
The Tohoku region has remained in the era called the Zoku-Jōmon era even after the Yayoi period began, and basically inherited a culture different from that of the Yamato administration and Japan's footsteps.
When the Taika Reform was carried out, a country called Dookukoku was set up in Tohoku (=the land of Ezo), but it was just a name and most of Tohoku remained unaffiliated.
From around this time, we will build a defense facility called a castle fence.
Tohoku Conquest
It was from 675 of the Saimei Emperor that we finally tried to conquer Tohoku in earnest. Around this time, a unified nation with the power of Sui and Tang was established on the Chinese continent, and the relationship with the Korean Peninsula became delicate.
Abe no Hirafu went to Tohoku to stabilize the country, and fought against Ezo and the forces that were hostile to Ezo, with a candy and a whip? I was able to attribute it.
However, there are problems with the subsequent development.
Tohoku is a place that is more susceptible to cold damage than other areas. That is why the hunter-gatherer society continued even after the introduction of rice cultivation. What happens if we cultivate it? I think it will be a situation where hunger is likely to occur (however, in the Nara period, famine did not occur as often as in the Edo period, because the Nara period was a time when we went into warming).
Chronology of the history of famine in Tohoku
It's related to the 713-800 part, but you can see that it has been a bad harvest, a bad harvest, and famine several times. It is thought that the reason why famine has decreased since the Heian period is that it overlaps with the warm period of the Middle Ages in earnest.
When I investigated the reason why the number of monks increased in the Nara period and the reason why Jianzhen came to Japan, I wrote that the temperature of smallpox from 735 was one of the causes of the epidemic. Warming begins around here, but it is still not stable.
The rebellion of the rebellious Ezo
Yet another cause of the rebellion was relocating the repatriated Ezo to various parts of the west of the Kanto region as a prisoner and cultivating them . .. It is believed that the terrible treatment of this prisoner was the beginning of the rebellion.
A large-scale Ezo clan, Korehari no Azamaro, who should have returned once due to a prisoner or famine, broke out in 780 and once passed through Tagajo, which is also a military base in the Tohoku region. It develops into a rebellion.
Since this has been going on for more than 30 years, Emperor Kanmu dispatches a large army with Ki no Kosami as the Seito Ambassador, but he is defeated. After that, Sakanoue Tamura Maro Becomes the Shogun General and builds Isawa Castle, and repatriates Aterui, the central figure of Ezo.
* Addition (October 30, 2015)
The Iji-no-Maro turbulence itself ended in a year, but before that, the Tohoku region had been rough and the state called the 38-year war had continued since around 770.
In the end, control extended to the Yoneshiro River basin on the Sea of Japan side, and to the construction of Shiwa Castle in the upper reaches of the Kitakami River in the north. It was good up to that point, but it would be financially difficult to carry out the two major projects with Heiankyo, so we will discontinue the two major projects.
There were twists and turns, but as a result, it was a great achievement of Emperor Kanmu to be able to control a wider area than before.
* Since the first sentence I wrote is difficult to read, I have moved it to another article.