Editing Balhae (section)

===Internal development===
During Heummu's reign, a trade route with Silla, called "Sillado" ({{Korean|hangul=신라도|hanja=新羅道|labels=no}}), was established. The Silla trade route began at the Eastern Capital located at the center of  Balhae's Yongwon Province, came down along the coast past what is now Hamgyong Province. This route, which also passed through Balhae's Southern Capital, was established for the purpose of conducting trade with Silla. Since the 1980s large numbers of archaeological sites related to Balhae have been excavated in North Korea; among those sites, the fortress at Bukcheong and the monastery site at Omae-ri in the city of Sinpo were locales engaged in the trade between Balhae and Silla. The route led from Pukchong, which was Balhae's Southern Capital, down along the coast to the Yonghung River; across the river was Silla's Chonjong (Jeonjeong) Prefecture.<ref>{{cite book |last1=Kim |first1=Eun Gug |chapter=An Enduring Window between North and South: Parhae and Silla |title=A New History of Parhae |date=2012 |publisher=Brill |page=79}}</ref> Heummu moved the capital of Balhae several times. He also established [[Shangjing Longquanfu|Shangjing]]/Sanggyeong, the permanent capital near [[Lake Jingpo]] in the south of today's [[Heilongjiang]] province around 756,{{sfn|Shin|2014|p=66}} stabilizing and strengthening central rule over various ethnic tribes in his realm, which was expanded temporarily. He also authorized the creation of the ''Jujagam''/''Zhouzijian'' ({{Korean|hangul=주자감|hanja=胄子監|labels=no}}), the national academy, based on the [[Guozijian|national academy of Tang]].