Editing Balhae (section)

=== Second Phase ===
The second phase saw the establishment of central departments and the ten guards, as recorded in the ''New Book of Tang''. The Zhengtangsheng/Jeongdangseong (政堂省), one of the [[Three Departments and Six Ministries|three central departments]], managed the military, recruitment, maps, war chariots, and weapons through the subordinate department known as the Zhibu/Jibu (智部). Subordinate to the Jibu were practical departments such as the Rongbu/Yongbu (戎部) and Shuibu/Subu (水部). For example, Yang Seung-gyeong, who was sent as an envoy to Japan in 758, held the central position of Boguk Daejanggun and Janggun (輔國大將軍兼將軍) and the regional position of Mokjeoju Jasa (木底州刺史), and he was also involved in managing national defense. However, the origins of these titles are difficult to trace, as they do not appear in the central official system. This indicates that Balhae organized its military by establishing the Jibu as the central department responsible for military affairs and its subordinate departments like the Yongbu or the Byeongseo (兵書).

Balhae had ten guards, including the "Left and Right Mengbenwei/Mangbunwi (猛賁衛), Left and Right Xiongwei/Ungwi (熊衛), Left and Right Piwei/Biwi (羆衛), Left and Right Nanwei/Namwi (南衛), and Left and Right Beiwei/Bukwi (北衛)."<ref name="MSB"/> Each guard had a Da Jiangjun/Daejanggun (大將軍) and a Jiangjun/Janggun (將軍). This system was likely modeled after the Tang Dynasty's 16 or 12 guards. Each guard had one Daejanggun and one Janggun, equivalent to the Tang Dynasty's Shang Jiangjun (上將軍) and Jiangjun (將軍). The ten guards protected the royal family and oversaw the local militia. In 1960, a seal inscribed with "Tianmenjun/Cheonmungun's Seal" (天門軍之印), belonging to one of Balhae's military units, was discovered southwest of the royal city of Sanggyeong Yongcheonbu. The discovery of this seal suggests that the army under each guard was responsible for guarding the gates of the royal city.

Meanwhile, the ''[[Shoku Nihongi]]'' records that in 728, among the envoys sent to Japan, there were officials such as You Jiangjun/Yujanggun (游將軍) and Guoyi Duwei/Gwaidowi (果毅都尉) Dezhou/Deokju (徳周). The title Guoyi Duwei was adopted from the Tang Dynasty's military system. In the Tang Dynasty, the Weibu (衛部) and the Zhechongfu (折衝府) were part of the military system. The Zhechongfu was further divided into upper, middle, and lower levels, with each level having one Zhechong Duwei (折衝都尉) and two Guoyi Duwei (果毅都尉). The Guoyi Duwei of the upper level was equivalent to the 5th rank, the middle level to the 6th rank, and the lower level to the 6th rank. In Balhae, the existence of the Guoyi Duwei/Gwaidowi indicates that Balhae likely adopted the Tang Dynasty's military system and established local militias in the provinces.

In particular, the military titles of envoys sent to Japan during the early period of Balhae, such as Janggun (將軍) or Boguk Daejanggun (輔國大將軍), suggest that the military system was already being organized at that time. The Jasa was a local administrative official overseeing the province, and the Daejanggun and Janggun were the highest military positions. The presence of various military titles among these envoys indicates that the system was already in the process of being organized.