1. Early Life and Background
Dae Ijin's exact birth year is unknown. He was the grandson of King Seon (Dae Insu, r. 818-830), the 10th King of Balhae, and the son of Dae Sindeok (大新德). Historical records indicate that Dae Sindeok passed away prematurely, leading to Dae Ijin, as the lineal grandson, succeeding King Seon. This lineage highlights the continued importance of direct royal succession within the Dae clan, even in cases where the immediate heir predeceased the reigning monarch. Upon his accession, Dae Ijin adopted the era name Hamhwa. Some historical accounts suggest that Dae Ijin may have claimed the title of Emperor, signaling Balhae's perception of itself as an independent empire rather than merely a vassal state, a view also echoed in Khitan historical records like the History of Liao. The Old Book of Tang records that upon King Seon's death in 830, Dae Ijin sent envoys to the Tang Dynasty, styling himself as Gwonji Gukmu (權知國務, "acting in charge of state affairs"). In response, Tang enfeoffed him as the King of Balhae, granting him the title of Yinqing Guanglu Dafu Jianjiao Mishujian Dududu (銀青光祿大夫 檢校秘書監 都督).
2. Reign
Dae Ijin's reign was characterized by extensive domestic reforms aimed at strengthening central authority and significant foreign relations that solidified Balhae's regional standing.
2.1. Domestic Policies
During his rule, Dae Ijin focused on comprehensive internal policies and institutional reforms that spanned administration, military, and cultural-economic development.
2.1.1. Administrative and Institutional Reforms
Dae Ijin vigorously pursued efforts to strengthen the centralized administrative system, building upon the foundations laid by his predecessors. By 850, his reign saw the full establishment of Balhae's local administrative structure, which mirrored the systems of the Tang Dynasty and Goguryeo. This comprehensive system included five capitals-a supreme capital, Sanggyeong (上京), and four secondary capitals: Junggyeong (中京), Seogyeong (西京), Donggyeong (東京), and Namgyeong (南京). Complementing these capitals were nineteen prefectures (府) and sixty-two districts (州). The nineteen prefectures were Longquan, Hyeondeok, Longwon, Namhae, Aplyuk, Jangnyeong, Buyeo, Makhyeol, Jeongni, Anbyeon, Suisin, Dongpyeong, Cheolli, Hwaewon, Anwon, Sukju, Dongju, Yeongju, and Liaodong. Each prefecture was governed by a Dae-wang (大王), implying a hierarchical structure with the central monarch overseeing these regional rulers, who belonged to powerful clans such as Go, Jang, Yang, Du, O, and Yi, with the Longquan Prefecture, which encompassed the capital, being directly administered by a member of the imperial Dae clan. The central government's administrative structure was modeled after the Tang's Three Departments and Six Ministries system, with Han characters serving as the administrative language, although the primary language of Balhae remained Goguryeo-based.
2.1.2. Military Reforms
Dae Ijin also implemented significant measures to enhance Balhae's military power and develop its military system. He organized a professional standing army through a conscription system (募兵制). This standing army included elite units responsible for guarding the imperial palace and the capital. Historical records, such as the Old Book of Tang, document the establishment of specific units, including the Left and Right Divine Strategy Armies (左右神策軍) and the Left and Right Three Armies (左右三軍), which comprised 120 divisions (一百二十司). The central army was composed of 10 units, with the Left and Right Maengbunwi serving as elite forces. Furthermore, Balhae's armed forces were strategically deployed across its 19 local provinces to ensure control and defense throughout the kingdom.
2.1.3. Cultural and Economic Development
Under Dae Ijin's reign, Balhae actively embraced cultural exchange with the Tang Dynasty. The kingdom dispatched numerous students to Tang China, some of whom notably passed the rigorous Tang imperial examinations (科挙), demonstrating the advanced level of scholarship in Balhae. This cultural integration fostered significant advancements within Balhae. Dae Ijin also promoted Buddhism, which was a vital aspect of the kingdom's cultural life, similar to its importance in the earlier Goguryeo kingdom. A Buddhist relief sculpture from 834 CE, during Dae Ijin's reign, found in Japan's Ohara Museum of Art, attests to the vibrant Buddhist art of the period, with an inscription that includes a poem praising Dharma. Economically, agriculture, livestock farming, and fishing remained crucial sectors, contributing to the prosperity and stability of the "Flourishing State in the East."
2.2. Foreign Relations
Dae Ijin's reign was characterized by active and complex diplomatic engagements with neighboring states and ethnic groups, reflecting Balhae's assertion of its independent status and its geopolitical influence.
2.2.1. Relations with Tang Dynasty
Despite Balhae's increasing self-perception as an independent empire, its formal relationship with the Tang Dynasty remained one of tribute and enfeoffment. Dae Ijin consistently dispatched envoys to Tang China; records indicate he sent 12 delegations during the reign of Emperor Wenzong and 4 during the reign of Emperor Wuzong, totaling 16 missions between 830 and 844. These diplomatic exchanges facilitated significant cultural and academic interaction. For instance, in 831, Dae Ijin sent his son, Dae Chang-hwi (大昌輝), along with several attendants, to Tang to study. In 832, he dispatched high-ranking officials such as Go Bo-yeong (高寶英) as part of a gratitude mission for his enfeoffment, accompanied by three students for study in Chang'an. An interesting episode from 833 to 835 involved a reciprocal visit by Zhang Jianzhang, an envoy from Tang's Youzhou province, to Balhae's capital, Sanggyeong. Dae Ijin offered him lavish hospitality, including banquets and numerous gifts such as precious items, fine horses, and patterned animal hides upon his departure. While maintaining these official ties, Balhae's actions, such as sending independent envoys to Japan, underscored its practical autonomy.
2.2.2. Relations with Neighboring Polities and Tribes
Balhae under Dae Ijin also engaged in conflicts and maintained specific relationships with surrounding tribes and states. The Heishui Mohe (黑水靺鞨), a tribal group to Balhae's northeast, launched coordinated attacks on Balhae's border prefectures of Anweon, Hwaewon, Cheolli, and Makhyeol in late 831. Dae Ijin responded swiftly, deploying four separate armies in 832 to repel the invasions and secure Balhae's territories. Balhae's territory had expanded significantly under King Seon, incorporating many Mohe tribes like the Chulli, Nugu, Yeokhi, and a significant portion of the Heishui Mohe, which Dae Ijin's reign further consolidated.
Relations with Silla to the south were complex and sometimes adversarial. Silla had constructed northern defense walls since 712 and maintained a constant military presence on its border with Balhae. In 836, Dae Ijin's Balhae became involved in a significant Silla succession dispute. The Silla merchant Jami, allied with Kim Rihong, sought assistance from Dae Ijin. Balhae troops were allegedly dispatched to intervene in the succession conflict following the death of King Heungdeok. These forces, alongside those of Kim Demyeong, attacked Gimjeong, a leading contender for the Silla throne, who was ultimately killed before his coronation. This intervention led to the enthronement of King Huigang by Kim Myeong, supported by Jami. After achieving their objective, the Balhae forces withdrew. This incident underscores Balhae's significant military and political influence in the region, even extending to internal affairs of neighboring states.
2.2.3. Trade and Cultural Exchanges
Trade and cultural exchanges were vibrant during Dae Ijin's reign, connecting Balhae with multiple polities across East Asia. Balhae maintained robust trade relations with the Tang Dynasty, Japan, Silla, and the Khitan tribes. The sea route between Balhae and Japan, traversing the Sea of Japan, became one of the most vital trade routes for Japan, solidifying Balhae's position as a crucial trading partner. Commodities such as weapons, horses, and food were exchanged, as exemplified by the trade between the Silla merchant Jami and Balhae's capital regions. Balhae's capital, Donggyeongseong (東京城, 동경성DonggyeongseongKorean), located in Longwon Prefecture, was described as a global city during this era, indicating the breadth of its economic and cultural reach, even extending to the distant Persian Empire.
3. Family
Dae Ijin's family played a significant role in the Balhae royal lineage.
- Grandfather:** King Seon (Dae Insu, r. 818-830), 10th King of Balhae.
- Father:** Dae Sindeok (大新德).
- Brother:** Dae Geonhwang (大虔晃, r. 857-871), who later succeeded him as the 12th King of Balhae.
- Children (Princes):** Dae Ijin had six recorded sons:
- Dae Chang-hwi (大昌輝)
- Dae Myeong-hun (大明訓)
- Dae Myeong-jun (大明俊)
- Dae Gwang-seong (大光晟) (also possibly referred to as Dae Seon-seong)
- Dae Yeon-gwang (大延廣)
- Dae Ip-ak (大立萼)
4. Death and Succession
Dae Ijin passed away in 857 CE, after a prosperous reign of 27 years. His temple name was Jangjong (莊宗). Despite having six recorded sons, including Prince Dae Chang-hwi who frequently served as an envoy and was familiar with external affairs, none of his children succeeded him to the throne. Instead, his younger brother, Dae Geonhwang (大虔晃), ascended to the Balhae throne. This unusual succession, bypassing the direct line of the monarch's sons, has led some modern historians to speculate about a potential military coup orchestrated by Dae Geonhwang to seize power. Dae Geonhwang was known to be an influential and astute figure within the royal family, having held significant positions, including managing the Two Departments and Six Ministries, during Dae Ijin's reign. This transfer of power suggests internal political maneuvering that deviated from conventional patrilineal succession practices.
5. Historical Assessment
Dae Ijin's reign is widely regarded by later historians as a period of significant prosperity and consolidation for the Balhae kingdom. His efforts to centralize administration and strengthen the military were crucial in maintaining the stability and power of the state. He successfully continued the legacy of his grandfather, King Seon, who had expanded Balhae's territory and established it as a dominant force in Northeast Asia. Under Dae Ijin, Balhae continued to be recognized by the Tang Dynasty as the "Flourishing State in the East" (海東盛國, 해동성국Haedong seonggukKorean), a testament to its advanced culture, strong economy, and diplomatic prowess. His active engagement in foreign relations, including military campaigns against tribal incursions and strategic interventions in Silla's internal affairs, further underscored Balhae's geopolitical influence. While the exact circumstances of his succession remain a subject of historical debate, his period of rule is generally viewed as one that solidified Balhae's golden age, characterized by robust governance, cultural achievements, and economic vibrancy.