Yu Deuk-gong: The Korean Scholar Who Rediscovered the History of Balhae
Series: Historical Figures
1. If Something Is Missing from History Books, Does That Mean It Never Happened?
When we study Korean history, we often learn about the Three Kingdoms of Korea: Goguryeo, Baekje, and Silla.
But what happened in the northern regions after the fall of Goguryeo?
While Silla continued to rule much of the southern Korean Peninsula, another kingdom emerged in the north.
That kingdom was Balhae (698–926).
Balhae existed for more than two centuries, yet its history was not presented as a separate, comprehensive account in the Samguk Sagi, a major Korean historical work compiled during the Goryeo Dynasty.
Centuries later, a Korean scholar began questioning this incomplete picture.
His name was Yu Deuk-gong (柳得恭, 1748–1807).
He believed that understanding Korea's past required examining the histories of both Silla and Balhae.
For this Tuesday's Daily Classics, let's explore how Yu Deuk-gong brought renewed attention to Balhae and what his work teaches us about historical research, critical thinking, and looking beyond familiar information.
2. Historical Background: Intellectual Change in Late Joseon Korea
Yu Deuk-gong lived during the late Joseon Dynasty, a period when Korean scholars were exploring new approaches to learning and social problems.
One important intellectual movement was known as Silhak, often translated as Practical Learning.
Scholars associated with this movement emphasized careful investigation, practical knowledge, and the study of real-world conditions.
Yu Deuk-gong developed his scholarship within this intellectual environment.
He interacted with prominent thinkers and writers, including Park Ji-won, Yi Deok-mu, and Park Je-ga.
Their discussions encouraged broader approaches to history, literature, and society.
In 1779, Yu Deuk-gong was appointed as a Geomseogwan, an official responsible for examining and editing books at the royal library and research institution known as Gyujanggak.
Gyujanggak had been established under King Jeongjo.
Working there gave Yu opportunities to study a wide range of historical and literary materials.
These experiences helped shape his interest in recovering overlooked aspects of Korean history.
3. The Publication of Balhaego in 1784
In 1784, Yu Deuk-gong completed an important historical work titled Balhaego (渤海考), meaning An Examination of Balhae.
At the time, surviving information about Balhae was scattered across different historical sources.
Yu gathered and organized references from earlier writings to reconstruct important aspects of the kingdom's history.
His work examined subjects such as Balhae's rulers, government officials, geography, administrative institutions, clothing, and products.
But his contribution went beyond collecting historical facts.
Yu also proposed a broader way of understanding the period.
He argued that the histories of Silla and Balhae should be considered together.
This perspective became associated with the concept of the Northern and Southern States (南北國).
Silla represented the southern state, while Balhae represented the northern state.
Rather than viewing the period only through the history of Silla, Yu emphasized the importance of recognizing both kingdoms.
This approach challenged the limitations of earlier historical narratives.
Although Balhaego does not meet every standard of modern historical scholarship, it remains an important work in the development of Korean historical studies.
Yu Deuk-gong demonstrated that revisiting overlooked records can change how we understand the past.
4. Today's Classical Quote
Original Classical Chinese
是謂南北國，宜其有南北國史。
— Yu Deuk-gong, Preface to Balhaego
English Translation
"These are called the Northern and Southern States, and there ought to be a history of the Northern and Southern States."
What Does It Mean?
Yu Deuk-gong believed that the history of the period could not be fully understood by examining Silla alone.
Balhae had also existed during those centuries.
Therefore, he argued that a historical account should consider both kingdoms.
His statement was not simply about adding more pages to a history book.
It reflected a concern that important parts of the past had been overlooked.
By examining sources that earlier historians had not brought together in a comprehensive account, Yu introduced a broader historical perspective.
His approach offers a valuable lesson for modern readers.
The information we already know may not represent the complete picture.
Sometimes, understanding a subject requires examining what earlier explanations have left out.
5. Workplace Lessons: Look Beyond the Most Obvious Explanation
Imagine that a company experiences a recurring software problem.
The development team initially suspects that a recent code update caused the error.
That explanation seems reasonable.
After all, the problem appeared shortly after the update.
But further investigation may reveal a different cause.
Perhaps an old server configuration is responsible.
Maybe the error occurs only when another system sends unexpected data.
Or perhaps several smaller issues are interacting.
If the team focuses only on the most obvious explanation, it may overlook important evidence.
Yu Deuk-gong's research offers a useful comparison.
He examined records from different sources to develop a more complete understanding of Balhae.
In a modern workplace, a similar approach means reviewing logs, checking previous changes, and comparing information before reaching a conclusion.
Good problem-solving often begins by asking what information might be missing.
6. Business Lessons: Study More Than Success Stories
When starting a business, people naturally look for examples of successful companies.
They study popular products, profitable strategies, and growing markets.
These examples can provide useful information.
However, focusing only on successful businesses may create an incomplete understanding of the market.
What about companies that failed?
What problems did they encounter?
Did they misunderstand customer demand?
Were their operating costs too high?
Did market conditions change?
Examining unsuccessful cases can reveal risks that success stories do not always show.
The same principle applies to customer research.
A business owner should not rely only on positive reviews.
Complaints, returns, and negative feedback may also contain valuable information.
Yu Deuk-gong's historical approach reminds us that a fuller picture often emerges when we consider sources that are easy to overlook.
Better decisions require examining both supporting evidence and information that challenges our assumptions.
7. Personal Growth: Question What You Think You Already Know
We often spend time searching for new information.
We read books, watch educational videos, and learn new skills.
But how often do we reconsider something we believe we already understand?
Sometimes, familiar knowledge becomes an assumption that we rarely question.
For example, we may continue using an old working method simply because it has always been done that way.
Or we may accept an explanation without checking whether newer information has become available.
Revisiting familiar subjects can reveal details we previously missed.
This does not mean we should doubt everything.
It means remaining open to new evidence and recognizing that our understanding may be incomplete.
Yu Deuk-gong did not discover Balhae as an unknown kingdom.
Instead, he gathered existing historical records and organized them into a more comprehensive account.
His achievement reminds us that meaningful discoveries do not always require entirely new information.
Sometimes, they begin with looking carefully at what is already available.
8. Key Takeaways
✅ Yu Deuk-gong was a Korean scholar and historian who lived during the late Joseon Dynasty.
✅ In 1779, he became a Geomseogwan at Gyujanggak, where he worked with historical and literary materials.
✅ In 1784, he wrote Balhaego, an important historical study of the kingdom of Balhae.
✅ He emphasized the importance of understanding Silla and Balhae together through the Northern and Southern States perspective.
✅ His work reminds us to examine overlooked information before accepting an explanation as complete.
9. Today's One Sentence
"Discovering something new is valuable, but recognizing what we have overlooked can be just as important."
We live in a world filled with information.
Every day, we encounter new articles, reports, technologies, and ideas.
Yet we do not always return to the information we already possess.
Sometimes, we assume that familiar explanations are complete.
Yu Deuk-gong approached history differently.
He examined scattered records and reconsidered how an important period of Korean history should be understood.
His work encouraged later readers to think beyond a single historical narrative.
The lesson remains relevant today.
When a problem seems difficult to solve, perhaps the answer is not always to search for something entirely new.
Sometimes, it is worth returning to the evidence we already have.
A forgotten document, an overlooked detail, or a different perspective may reveal something important.
The next time you face a difficult decision, consider asking yourself:
"What important information might I be overlooking?"
That question may lead you toward a more complete understanding.
💬 Today's Question
Have you ever revisited something you thought you already understood and discovered an important detail you had previously missed?
