Balhae (Korean: 발해; pa̠ɽɦɛ̝, , Бохай, ), also rendered as Bohai, was a multi-ethnic kingdom established in 698 by Dae Joyeong (Da Zuorong) and originally known as the Kingdom of Jin (震, Zhen) until 713 when its name was changed to Balhae. At its greatest extent it corresponded to what is today Northeast China, the northern half of the Korean Peninsula and the southeastern Russian Far East.
Balhae's early history involved a rocky relationship with the Tang dynasty that saw military and political conflict, but by the end of the 8th century the relationship had become cordial and friendly. The Tang dynasty would eventually recognize Balhae as the "Prosperous Country of the East". Numerous cultural and political exchanges were made. Balhae was conquered by the Khitan-led Liao dynasty in 926. Balhae survived as a distinct population group for another three centuries in the Liao and Jin dynasties before disappearing under Mongol rule.
The history surrounding the origin of the state, its ethnic composition, the modern cultural affiliation of the ruling dynasty, the reading of their names, and its borders are the subject of a historiographical dispute between Korea, China and Russia. Historical sources from both China and Korea have described Balhae's founder, Dae Joyeong, as related to the Mohe people and Goguryeo.
Balhae was founded in 698 by Dae Joyeong (Da Zuorong) under the name (진, Jin), read as tsyinH in Middle Chinese. The kingdom's name was transcribed as in Chinese, with the same Middle Chinese reading as .
In 713, the Tang dynasty bestowed the ruler of Jin with the noble title "Prince of Commandery of Bohai (Balhae)" (渤海郡王). In 762, the Tang formally elevated Balhae to the status of a kingdom. The kingdom's territories did not overlap with the Bohai Commandery. According to Jin Yufu, the Tang referred to the state as Mohe (Malgal, name of the ethnic group) until 713, and "Balhae" was possibly used as a different transcription of the same name. According to the New Book of Tang, the state was called Mohe before it received investiture from China and assumed the name Bohai.