Josaku (official defense site) (城柵)
Josaku is a historical term for a government office with defending facilities that was located to govern the north part of present-day Niigata Prefecture and the Tohoku region under the ritsuryo system during the ancient Japan. Since it is referred to as 'XX jo' or 'XX saku' in historical documents, 'josaku' is used here as a generic term. It is believed that both 'jo' and 'saku' were read as 'ki' in those times. The saku that were located as military footholds by the Abe clan of Oshu and the Dewa Kiyohara clan during Zen Kunen no Eki (the Early Nine Years' War) and Gosannen no Eki (the Later Three Years' War) were different in nature from 'josaku,' so they are generally not included in the 'josaku' discussed here.
Areas along Josaku in the Japan Sea
The Nutari no Ki located about present-day Nutari, Niigata City in 647 is the first josaku ever recorded.
In 648, Iwafune no Ki was located around today's Iwafune, Murakami City.
A josaku named Tsukisara no Ki is also mentioned in "Nihon Shoki" (Chronicles of Japan), but it is unclear when and where it was located.
Additionally, since an article dated August 14, 709 of "Shoku Nihongi" (Chronicle of Japan Continued) records that weapons were transported to Dewa no Ki, it is suggested that Dewa no Ki had existed by then. Although Dewa no Ki is considered to be located in Ideha gun, or the present-day Shonai region, its detailed location is unknown. In addition, the fact that Ideha (another name for Dewa) gun was established in 708 suggests that it was located around this time period. In 712, Ideha gun was promoted to Dewa Province, with Dewa no Ki being its provincial capital. Subsequently, it is considered that Dewa no Ki was relocated to present-day Akita City on February 8, 734, and was renamed Akita-jo Castle. However, with its location being in the middle of the northerners' residential area, it was subject to frequent attacks in conflicts with them. Therefore, its provincial capital is believed to have been relocated to 'Kawabe no fu' in 804. But Akita-jo Castle was not abandoned; with its military functions being reinforced, a provincial governor resided and took the initiative. For this reason, Dewa no suke (assistant governor of Dewa Province) came to be referred to as Akita-jo no suke. Although there are various theories as to where its provincial capital was located, it has been concluded that it was located in Kinowa no Ki in today's Sakata City.
759 saw the function of Okachino Ki Castle in Ogachi gun. The castle's detailed location is unknown, with some identifying it as the remains of Hotta no Ki, but it is widely believed that Hotta no Ki was never recorded in documents.
Areas along Josaku in the Pacific
Taga-jo Castle was founded by ONO no Azumahito in 724. Prior to this, the capital of Mutsu Province is considered to have been Koriyama Ruins in present-day Nagamachi, Sendai City.
The names of Taga no Ki, Tamatsukuri no Ki, Shikama no Ki, Nitta no Ki and Ojika no Ki are seen in the article dated 737 of "Shoku Nihongi," which records that four josaku were located at almost the same time in present-day Miyagi Prefecture.
The late 8th century saw the foundation of Mono-jo Castle, Iji-jo Castle and Kakubetsu-jo Castle. In the 9th century, josaku were also started to be founded in the present-day Iwate region, as Isawa-jo Castle was founded by SAKANOUE no Tamuramaro in 802, to which Chinju-fu (Pacification and Defense Headquarters) were relocated from Taga-jo Castle. Shiwa-jo Castle was founded the following year, but being frequently damaged by flooding of Shizukuishi-gawa River, it was abolished in 811 and relocated to Tokutan no Ki, or Tokutan-jo Castle.
Roles of Josaku
Josaku acted as outposts designed to exterminate barbarians, and were located as military footholds in the areas that militarily brought northerners into submission. Many immigrants called sakuto were sent from the Hokuriku and Kanto regions to these areas, which were under the ancient Japanese government, and which also served as a foothold for immigrants, an office for governance, and a site to hold banquets for subordinate barbarians who paid tributes to. In response to this, kokushi shitokan (four officials of the provincial governor), shisho (people who performed miscellaneous duties about documents) and chinkan (officials in charge of pacification and defense) were assigned to manage and govern each josaku. Soldiers were also dispatched as military force from the Bando countries to pacify and defend their area. Given the excavated materials, it is viewed that Akita-jo Castle served as a site to entertain foreign envoys from countries such as Bokkai, or Bohai, and to trade with the northern peoples, in addition to the functions described above.
The castle lords had great authority and shared a part of the power of kokushi (provincial governor), as they ruled gunji (local magistrates) appointed to the gun (province) and barbarians residing within, and had a command of an army of soldiers and barbarians. Mutsu was exempt from paying Soyochoyo (Yo of Soyocho tax system; Labor or alternative goods) to the central government, and those were used as financial resources for the management of josaku.
Sakuko, or immigrants, were located, according to where they were from, around josaku in which they lived and cultivated the land. As an illustration of this, Go-mei, the ancient Ou, and Bando, share the same history as to sakuto. However, sakuto lived harsh lives, and many of them got away. "Ruiju sandai kaku" (Assorted regulations from Three Reigns) indicates that Daijokanpu (official documents of the Daijokan, the office of the supreme political leader) were issued in 811 to forbid confiscating peasants' newly cultivated land in Mutsu, Dewa provinces. Other official notices were issued on several occasions to exempt sakuto from a portion of their land tax, thereby comforting them.
But josaku went into a rapid decline since around the 10th century along with the end of the government's policy against barbarians, and by the 11th century, it had disappeared from historical documents as well as archeological records. It is considered that the barbarians and immigrants had been increasingly intermingled since around the 10th century, which put the roles of josaku to an end. Meanwhile, the Abe clan of Oshu and the Kiyohara clan, who were chiefs of barbarians, gained power.
Landscape of Josaku
According to archaeological findings, a general josaku was consisted of an office mounted on an elevated hill, around which the residents of soldiers were located, with earthen walls and fences made of lumber around them, as wells as watchtowers to reinforce defenses. In the surrounding area were outposts for immigrants, who retreated into the josaku in emergencies.
For the most part, the descriptions '凡縁東辺北辺西辺諸郡人居、皆於城堡内安置。其営田之所、唯置庄舎。至農時堪営作者、出就庄田 謂、強壮者出就田舎、老少者留在堡内也。収歛訖勒還 謂、要勒而還於城堡也。' in Yoro-ryo (Yoro Code) correspond to what has been found in archaeology.
Nutari no Ki, 647, unknown, Nuttari gun, unknown, existent by the Yoro years (717-724)
Iwafune no Ki, 648, unknown, Iwafune gun, unknown
Tsukisara no Ki, unknown, unknown, unknown, unknown, existent by 658
Dewa no Ki, about 760, Ideha gun, unknown, Ideha gun, relocated to Akita in February, 734, Dewa Kokufu (the provincial capital of Dewa Province)
Akita-jo Castle, about 760, about 11th century, Akita gun, (located after abolition of Akita-jo castle, former site of Akita-jo Castle, its Kokufu function relocated in 804
Kawabe no fu, 759, unknown, Kawabe gun, unknown
Okachi no Ki, 759, unknown, Ogachi gun, unknown
Yuri no Ki, unknown, unknown, Yuri gun, unknown, article dated August 23, 780 of "Shoku Nihongi"
Hotta no Ki, beginning of 9th century, end of 10th century, remains of Hotta no Ki, theories of Kawabe fu, Okachi no Ki, josaku unrecorded in documents, and second Ogaki no Ki
Kinowa no Ki, 9th century, 10th century, possibly Ideha gun, remains of Kinowa no Ki, Dewa Kokufu
Taga-jo Castle, 724, medieval period, Miyagi gun, former site of Taga-jo Castle, Mutsu Kokufu, kokufu function moved to kokushi's residence in the vicinity in mid 10th century
Tamatsukuri no Ki, about 737, unknown, Tamatsukuri gun, possibly Kodera Ruins, later relocated to Tamatsukuri no Ki or possibly Miyazawa Ruins
Shikama no Ki, about 737, unknown, Shikama gun, possibly Jo Ruins
Nitta no Ki, about 737, unknown, Nitta gun, the presumed former site of Nitta no Ki
Ojika no Ki, about 737, unknown, Ojika gun, possibly Akai Ruins
Mono-jo Castle, 759, unknown, Mono gun, former site of Mono-jo Castle
Iji-jo Castle, 767, beginning of 9th century, Kurihara gun, former site of Iji-jo Castle
Kakubetsu-jo Castle, 780, unknown, unknown, unknown
Isawa-jo Castle, 802, about late 10th century, Isawa gun, former site of Isawa-jo Castle
Nakayama no Ki, prior to 804, unknown, unknown, unknown, "Shoku Nihongi"
Shiwa-jo Castle, 803, 811, possibly Shiwa gun, former site of Shiwa-jo Castle, relocated to Tokutan-jo Castle and abolished
Tokutan-jo Castle, 811, about mid 9th century, Shiwa gun, former site of Tokutan-jo Castle