After consolidating the forts on the Michinoku front, a new fort was constructed on the Ideha (northwestern) front. The government created a second Fort Ideha at Takashimizu Hill (different from the original fort constructed there) in Akita in Tenpyou 5 (AD 733). This was a risky decision because of its isolation from the main Japanese fort line in Michinoku. They were counting on the cooperaion from a group of Akita Emishi. After the completion of this fort the next project was the construction of a road from Michinoku to the new Ideha fort. Oono proposed that a road be built through Okachi.
Fujiwara no Maro, Minister of Military was appointed to Setsu Holding Grand Delegate (Jisetsu Tai Shi), Saeki no Sukune Toyohito and Sakamoto no Asomi Uzumasa to the vice delegate (Delegates had the same rank as a general at this time).
Maro's report gives details of this campaign: Japan mobilized one-thousand cavalry from six countries: ''One-hundred ninety-six were led by general Azumahito, four-hundred fifty-nine were divided to five (or three?) forts of Tamatsukuri and others. Maro and others led the remaining three-hundred forty-five and were stationed at Fort Taga." Sakamoto no Uzumasa was stationed at Fort Tamatsukuri, while Ootomo no Minomaro was stationed in Fort Niita, and Kusakabe no Oomaro in Fort Oshika.
Before the start of the operation, two Emishi were sent to explain the intentions of the army to the local people. Toota no Kimi Ohito, a field Emishi and district Orner of Toota, was sent via the sea road while Waga no Kimi Keyasuru, a subject Emishi, was sent via the mountain road.
The forces of Oono no Azumahito consisted of one-hundred ninety-six cavalry of Ki no Asomi Murashi, four-hundred ninety-nine Peace Guards, five-thousand Michinoku country soldiers, and two-hundred forty-nine subjected Emishi. They left from Fort Shikama on March 1, reached the station of Oomuro in a day. Five-hundred soldiers and one-hundred forty subject Emishi led by Tanabe no Huhito Naniwa, the Governor of Ideha, met Oono there. At once road construction began. Oono built the road to Tamano till March 11 when snow blocked further progress. He returned to Taga Castle.
As Oono continued to build the road and reached Hirahoko Mountain the leaders of Okachi village came to Tanabe and said, ''We heard that the army wanted to enter our village. We cannot stop the fear [of the people], so came and asked to surrender." They hoped the army would not enter Okachi.
Oono told Tanabe, ''The Barbarians very often use ploys. Their word is not consistent, so I cannot rely on it. If they mention it again then we will make peace together."
Tanabe no Naniwa said, ''We planned that the army would enter the rebel's territory for teaching the barbarians, building a castle and letting people move there to stay, and not for harming them. If we do not agree to their request, the barbarians will harbor a grudge and escape to the mountains or the plains. Many efforts [to suppress the barbarians] with little success to show for it is not a good strategy. Instead, let us show them (the Emishi) the power of the army and make them obey. Afterwards, Naniwa will teach with happiness, and act with tolerance. Then the castle will be easy to defend, and the people [will] live in long lasting peace."
Oono no Azumahito agreed: "[The] principal strategy of Azumahito was to enter into rebel's territory early, to seed and store crops to save in the cost of transportation. However, this spring it snowed twice that of a normal year, so we could not enter early and sow seed. Heaven's timing is like this. My original plans had to change. To build a castle can be performed in one morning, but to defend a castle is done with men. Keeping men is done with food. When the time for sowing is lost, what can we do? Military operations should act when there is an advantage, and stop action when the advantage is lost. So we will go back with the army, and make a castle in a future year. This was the reason that I, Azumahito, is entering into the rebel's territory at this time, and requested that the general (Fujiwara no Maro) defend Fort Taga. Now that the new road has opened the terrain is more familiar. In a later year we can succeed even if I do not enter myself."There is a record from Suruga country (kuni) on the Pacific coast that one-hundred fifteen Emishi from Michinoku passed through this year (the country provided for their food). Either some battles were fought at this time, or the Emishi may have been forcibly resettled.The operation did not succeed. However, we can learn much about the Japanese strategy from this campaign. When we think about why this apparent failure was recorded with detail as opposed to why many other expeditions did not get recorded we have to look at the end result: this policy succeeded where others had failed. The murders of high officials suggested an atmosphere of dangerous unrest between the local Emishi and the colonizing Japanese. Massive mobilizations of the army were called only after a high official was killed. Probably many small battles or skirmishes took place between the intervals of major campaigns. However, the individual fighting capacity of the Emishi was superior to the Japanese. The Emishi practiced guerilla warfare. Massive Japanese armies would come into the region, but would not be able to find or engage Emishi forces. By the time that a large Japanese army arrived the Emishi would scatter into the mountains. The Japanese would then forcibly settle several hundred Emishi to inner Japan as punishment. But this 'victory' was temporal because the Emishi would come out and attack the forts as soon as the army left. And due to the prohibitive cost of maintaining a large "continental style" army in the field, it could not be maintained for long. This earlier strategy was doomed to failure.A sustainable defensive strategy was a prominent character in Azumahito's plan. He gathered a sufficiently large force to evade attack. And even when he had an overwhelming force he did not try to destroy the enemy. Instead he conserved his forces and concentrated them along the fort lines to make a sustainable front making it difficult for the Emishi to deploy their earlier strategy of attacking after the army left. It was a political strategy for preventing resistance. Since Tenpyou 9 (737) until Houki 5 (774), there is no mention of military action in the northeast. It was an important success for the Japanese government.
This success was due to Oono no Azumahito. His superior, Fujiwara no Maro, admitted Oono was the real commander general in this campaign. In later records the government referred to this as Azumahito's Law, and his policies regulated the area for a long time.