Baekje’s Lost Maritime Empire

The Phantom Empire in the Archives

Friends, we are now aboard a Baekje ship. Its tightly woven hull cuts through the rough waves, and the majestic sails are filled with the winds of the West Sea. Amid the creaking song of the mast and the sailors’ vigorous chants, we travel back in time to trace the traces of a phantom empire roaming the archives of East Asian history. This is the story of Baekje’s lost maritime network, ‘Damro (檐魯)’.

Modern historians piece together fragments of scattered records to reconstruct the past. A single line in a Chinese chronicle, a mysterious inscription on a strangely shaped sword, a curious birth legend of a prince recorded in ancient Japanese texts. Individually, these may seem like mere intriguing historical footnotes. But when woven together into the single thread called ‘Damro,’ we finally face the outline of a vast forgotten picture.

Baekje’s power was not a territorial empire with clear borders like Rome. It was a fluid, multi-layered maritime network empire organically connected by the sea as a highway. The key to understanding this network is the concept of ‘Damro.’ Damro was more than a simple administrative district; it was Baekje’s unique flexible governance system adapted to different geopolitical contexts. Within the Korean Peninsula, it functioned as an ‘administrative Damro’ to strengthen royal authority and control local powers; on the Chinese continent, it served as a ‘colonial Damro’ to check Goguryeo and secure trade; and across the sea in Wa (Japan), it operated as a ‘hegemonic Damro’ bound by kinship and culture.

This article is a grand voyage reconstructing the reality of the Damro system through four decisive episodes from Baekje’s western and eastern spheres of influence. First, we will follow faint records in Chinese chronicles to visit Baekje’s frontline base established on the continent. Next, we will uncover the secret held by a single sword that defined Baekje-Wa relations and gauge the depth of the two countries through the legend of a prince born on a small Japanese island. Finally, we will witness a massive cultural coup that transformed Wa’s history through the new ideology of Buddhism.

At the journey’s end, we will realize what Baekje’s forgotten maritime hegemony looked like and how their empire functioned. This is a task of drawing the map of a lost empire and restoring their great name, once engraved on the sea but washed away by indifferent waves. Now, it is time to raise the sails.

Part 1: The Western Border – A Foothold Established in the Central Plains

Chapter 1: The Liaoxi Campaign, an Ambitious Episode

The story begins on a summer morning in the late 4th century during the reign of King Geunchogo, Baekje’s greatest ruler. In the main hall of the royal palace in Hansung, an envoy who just crossed the Yellow Sea reports excitedly.

“Your Majesty! Following your command, we have crossed the Yellow Sea and reached Liaoxi. The land had become ownerless due to the chaos of the Sixteen Kingdoms. Our navy seized the coast and advanced inland; local forces dared not resist and submitted. We have now established a Baekje county there named ‘Jinpyeong,’ announcing to the world that Baekje’s prestige has finally reached the continent!”

King Geunchogo nods with a satisfied smile. This was not merely territorial expansion but a sharp dagger piercing the rear of Goguryeo, which was constantly pressing south and tightening Baekje’s throat. At the same time, it proved to their ally Dongjin across the sea that Baekje was no longer a small frontier state but a powerful partner capable of influencing continental affairs. This scene is reconstructed from fragmentary records left in later Chinese histories, revealing Baekje’s bold ambition.

Evidence in Literature: An Empire Inscribed in Faded Ink

The core evidence for Baekje’s continental advance, the so-called ‘Liaoxi Campaign Theory,’ surprisingly comes not from Baekje’s own records but from Chinese Southern Dynasties’ histories—like finding a lost diary of our grandfather in someone else’s attic.

The first clue appears in the 5th-century 『Song Shu』 (Book of Song), which offers a brief but striking sentence:

“Later, Goguryeo campaigned and took control of Liaodong, and Baekje campaigned and took control of Liaoxi. The area governed by Baekje was called Jinpyeong County.”

This record treats Goguryeo’s control of Liaodong and Baekje’s control of Liaoxi as contemporaneous and natural facts, even specifying the administrative name ‘Jinpyeong County,’ enhancing credibility.

This remarkable record was not a one-off claim. Subsequent Southern Dynasties histories repeatedly confirmed it. The 7th-century 『Liang Shu』 and 『Nan Shi』 contain nearly identical sentences stating that during the Jin dynasty, Goguryeo took Liaodong, and Baekje occupied two counties in Liaoxi named Jinpyeong, establishing Baekje counties. The 9th-century administrative geography 『Tongdian』 went further, pinpointing the location between present-day Liucheng and Beiping in eastern Hebei Province.

Ongoing Debate: Searching for the Reality of the Phantom County

However, scholarly debate over these records has been intense for the past century.

• Proponents argue from the international context of the 4th century, when the Chinese continent was in turmoil with many competing states. They consider it plausible that Baekje, with a powerful navy under King Geunchogo, exerted military influence along Liaoxi’s coast.
• Skeptics point to the silence in Baekje’s own records and hostile Northern Dynasties’ histories, questioning why such a significant event is absent. They suggest Southern historians may have copied exaggerated claims by Baekje envoys seeking to elevate their status.

‘Liaoxi Damro’ as a Diplomatic Declaration

Regardless of the debate’s outcome, the repeated mention of the Liaoxi campaign in Southern histories is significant. East Asia’s international order then resembled a giant chessboard with the northern Goguryeo-Northern Dynasties alliance opposing the southern Baekje-Southern Dynasties alliance.

In this diplomatic arena, the claim “We secured a military base in Liaoxi right next to Goguryeo’s heartland” was Baekje’s most effective declaration to impress its invaluable alliance with the Southern Dynasties. Thus, Jinpyeong County in Liaoxi symbolized Baekje’s geopolitical ambition and successful diplomacy more than actual territorial size. It was the westernmost ‘colonial Damro’ of Baekje’s maritime empire, a maritime milestone pointing toward the continent.

Part 2: Expansion Eastward – Another Baekje Established in Wa

Chapter 2: The Sword of the Vanquished, the Mystery of the Seven-Branched Sword

The scene shifts to 372 AD in a royal workshop in Baekje’s capital Hansung. Red flames dance in the furnace, and dozens of artisans sweat profusely as they hammer iron, shaking the heavens and earth. Before them, a strange and sacred sword gradually takes shape: the divine sword Seven-Branched Sword (칠지도, Qīzhīdāo), with three branches extending from each side of the blade like tree branches, totaling seven.

This sword was not a mere weapon. Commissioned by the crown prince (later King Geungusu), it was a highly diplomatic symbol forged with all Baekje’s technology, artistry, and political will. Soon, it would be shipped across the rough waters of the Korea Strait to the king of Wa. The moment the Seven-Branched Sword arrived at Wa’s court, the relationship between the two countries was destined to enter a new order.

Inscription and Debate: The Language of Power on the Blade

Today, the Seven-Branched Sword is preserved like a sacred relic deep inside Isonokami Shrine in Nara Prefecture, Japan. The century-long debate surrounding this sword focuses on the 60-character gold inscription on the blade, especially the phrase “宜供供侯王” (meaning roughly “should be presented to the Marquis King”).

• Gift Theory (Downward Bestowal) – Korean Academic Consensus: The term ‘侯王’ (Marquis King) is used when an emperor grants a vassal title. Thus, the phrase means “rightfully made for the Marquis King (the Wa king),” interpreting the sword as a gift bestowed (下賜) by the superior Baekje king to the vassal Wa king.
• Presentation Theory – Traditional Japanese Interpretation: Based on the 『Nihon Shoki』, it claims Baekje presented (献上) the sword as a tribute, pledging allegiance to Wa, the superior country.

Asymmetric Interdependence: Rewriting the Grammar of Alliance

The Seven-Branched Sword perfectly embodies the complex, mutually dependent yet hierarchical relationship between Baekje and Wa at the time. Baekje was the culturally and technologically advanced ‘senior partner,’ while Wa was the militarily important ‘junior partner.’

By gifting this technologically advanced sword, Baekje asserted cultural superiority and politically defined the hierarchy by granting the title ‘Marquis King.’ The era name ‘Taihe (泰和)’ inscribed on the sword, unique to Baekje, further supports this imperial confidence. The Seven-Branched Sword was a great diplomatic declaration forged in steel.

Chapter 3: The Prince Born on an Island, the Birth of King Muryeong

In 461 AD, Baekje’s royal fleet cuts through the rough waters of the Korea Strait toward the Japanese archipelago. Onboard is Prince Gonji, brother of King Gaero. Remarkably, the king’s consort, pregnant with the royal child, is also aboard.

The fleet lands on a small island at the northern tip of Kyushu, called Gakarashima. There, the queen gives birth to a boy who would become Baekje’s 25th king and a great revival monarch, King Muryeong (武寧王). Born on the island, the boy was called ‘Sama (斯麻),’ meaning ‘island.’

Strange Record in 『Nihon Shoki』 and Archaeological Confirmation

This incredible story is recorded in surprising detail in Japan’s 『Nihon Shoki』. The legendary tale became reality in the summer of 1971 when King Muryeong’s tomb was discovered intact in Gongju, South Chungcheong Province.

The most decisive evidence was the wooden coffin encasing the king’s body. Scientific analysis proved it was made from Japanese golden pine (Pinus densiflora), native only to southern Japan. The prince said to be born on a small Japanese island was lying in a coffin made of Japanese wood 1,500 years later.

Wa as Baekje Royalty’s ‘Strategic Rear’

King Muryeong’s birth legend clearly shows what Wa represented to Baekje’s ruling class: not a dangerous unknown land but a safe zone deeply integrated within Baekje’s elite influence—a ‘Strategic Rear.’ As Goguryeo pressure intensified, Wa was a trusted refuge to preserve the royal lineage safely. The Damro established in Wa was not governed by military conquest but was a fully developed ‘hegemonic Damro’ bound by kinship, trust, and shared interests.

Chapter 4: The Rise of the Soga Clan, a Coup in the Name of Buddha

In 587 AD, on the plains of Mount Shigi in Kawachi Province, Japan, the military aristocratic Mononobe clan, guardians of traditional Shinto gods, and the Soga clan, descendants of Baekje immigrants and champions of the new Buddhist ideology, fought a decisive battle for the fate of ancient Japan. This ‘holy war’ was effectively a grand coup completing the victory of the Baekje-style state model on Japanese soil.

Seeds of Conflict: Buddha Crossing the Sea

The conflict’s seed was sown about 50 years earlier in 538 when Baekje’s King Seong officially sent Buddhist statues and scriptures to the Wa court.

• Soga clan (Pro-Buddhism faction): Closely connected to the Korean Peninsula, they saw Buddhism as a powerful ideology to complete an advanced centralized state.
• Mononobe clan (Anti-Buddhism faction): Traditional military aristocrats who viewed Buddhism as a foreign plague threatening their vested interests.

War and Aftermath: Dawn of the Asuka Period

The Soga clan’s decisive victory at Mount Shigi destroyed the Mononobe clan and rose to supreme power in the Wa court. This victory opened the door to the Asuka period, the golden age of ancient Japanese culture. The Asuka culture was essentially ‘Baekje culture,’ blossomed by monks, scholars, and artisans who came from Baekje.

The Buddhism Baekje ’exported’ was an extremely effective soft power that achieved their desired outcome in this war. Baekje did not need to send large armies to conquer Wa; instead, they conquered their spirit through culture and religion, ensuring the Japanese archipelago remained their most loyal partner in the maritime network.

Part 3: The Empire’s Arteries – Ships, Trade, and Governance

Chapter 5: Masters of the Yellow Sea, Baekje Ships and Sea Routes

Baekje’s vast maritime network called ‘Damro’ was sustained by the era’s most advanced shipbuilding and navigation skills. With this formidable naval power, Baekje roamed East Asian seas as if they were their own backyard.

The sea routes these ships traveled were like the empire’s arteries:

• Northern Route (Chinese coastal route): Military and diplomatic path to Liaoxi and Shandong Peninsula.
• Direct Route (Southern Chinese route): Route importing the latest cultural goods from Southern China.
• Eastern Route (Japanese route): Path securing alliances and resources with Japan.

Through these routes, envoys traveled, armies moved, and goods exchanged. Active relay trade was the economic heart that kept the Damro network constantly moving.

Chapter 6: The Damro System, a Network of Kings and Kin

Damro was originally an innovative local governance system devised as Baekje unified the various small states of Mahan. 『Liang Shu』 records, “The country had 22 Damro, all governed by the king’s sons and relatives.” Trusted family members were dispatched as local officials to strengthen central authority.

Comprehensive Understanding of the Damro Network: The Empire’s Three Faces

‘Damro’ was not a single concept but a multi-layered governance strategy flexibly applied according to Baekje’s diverse geopolitical situations.

These three Damro types were organically connected to form the vast Baekje maritime empire.

Echoes of a Lost Empire

Through the four reconstructed episodes, we glimpsed that Baekje’s Damro empire was a vast maritime network stretching from the Chinese coast to the heart of Japan, built on strong naval power, sophisticated diplomacy, and overwhelming cultural prestige.

So why did such a powerful empire become a ’lost’ entity in our history? When the capital fell to the Silla-Tang alliance in 660, most official histories known as the ‘Baekje Three Books (百濟三書)’ were lost, and under the unified Silla-centered historiography, Baekje’s great maritime activities were naturally diminished or forgotten.

Although the political network called Damro vanished into history 1,400 years ago, its echoes remain with us. They live on in the shared cultural DNA of regional states and in countless artifacts still resting beneath land and sea, waiting to tell new stories. As long as the vast sea keeps the memory of that day, our quest for the lost empire will continue.