Akita Jonosuke (秋田城介)
Akita Jonosuke was the title under the Ritsuryo system granted to the provincial officer who had been given complete jurisdiction over Akita-jo Castle in Dewa province. Because holders of this position were the "suke" (assistant governor) of Dewa province and had been assigned to Akita-jo Castle, the position began to be called Akita Jonosuke.
In 780 a plan for how to strengthen Akita-jo Castle was worked out, under which Dewa's provincial officers would make the castle their permanent home and the seat of provincial government. According to the "Mutsuwaki" (Tales of Mutsu), in the opening skirmish of the Former Nine Years' War, Mutsu FUJIWARA no Narito attacked the Akita Jonosuke TAIRA no Shigenari as well as Yoriyoshi ABE, and in December 1051 was defeated in 'the Battle of Onikiribe'; this particular Akita Jonosuke, TAIRA no Shigenari, was the same TAIRA no Shigenari (though the "Shige" in his name was written differently) who was the son of the Yogo Shogun TAIRA no Koreshige, and Shigenari's descendants began calling themselves the Jo (castle) clan.
The Jo clan, who were natives of Echigo province (and thus are known as the Echigo Jo clan), supported the Taira faction during the Jisho-Juei War, and as a result fell upon hard times, until in 1201, Sukemori JO raised a rebel army at Tossaka-jo Castle which was suppressed by the Kamakura shogunate; from that point onwards, the Jo clan never again appeared in the annals of history.
According to the "Azuma kagami" (Mirror of the East), TAIRA no Shigenari was the last person to be appointed Akita Jonosuke, until in 1218 the shogunate appointed Kagemori ADACHI, leader of the powerful Adachi clan, to the position of Dewa no suke (assistant governor of Dewa), and started calling him Akita Jonosuke. The shogunate did this because being allowed to use the title Akita Jonosuke was considered a great honor by warrior families. Thereafter, the Adachi clan continued to inherit the title of Akita Jonosuke for the rest of the Kamakura period (and in fact the Shimotsuki Incident, in which Yasumori ADACHI was overthrown and ruined, is also called the 'Akita Jonosuke's rebellion'). During the Muromachi period, the Ando clan, who controlled the area in and around Akita, called their own clan head Akita Jonosuke.
In 1575, Nobutada ODA, Nobunaga ODA's eldest son and heir, was appointed Akita Jonosuke. This is seen as one portion of Nobunaga's larger strategy to unify the country. In 1589, under Hideyoshi TOYOTOMI's rule, Sanesue AKITA, a descendant of the Ando clan, was termed Akita Jonosuke, and in addition the surname of his family was changed to AKITA (the Akita surname comes from Akita Jonosuke). The Akita clan's fief was relocated to Hitachi province after the Battle of Sekigahara, which prompted them to change their surname to IKOMA, but years later they restored their surname to Akita and moved again, to Miharu in Mutsu province, staying this way until the Meiji Restoration.