A History of Korea Pt 5
By Michael Downey
Japan and Korea are close neighbors. From Incheon International Airport to Narita near Tokyo, it is just a two-hour flight. Korean golfers, seeking to avoid exorbitant domestic prices, often book a tee time and hop over to Japan—returning to Seoul in time for dinner and drinks. The two countries share many cultural similarities, and even their languages have some common ground. Yet, as with many close neighbors—or even siblings—there is often tension. Throughout their long history, Japan and Korea have clashed many times.
It all began on the southern tip of the Korean Peninsula, closest to the Japanese islands. The Gaya Confederation grew out of the Samhan Confederations, particularly Byeonhan. We know that Gaya was located in the central southern region of the Korean Peninsula between Baekje and Silla, though the exact borders and towns of the confederation are unclear and vary depending on sources.[1]
The founding of Gaya dates to between the 1st and 2nd centuries CE, depending on whether the Byeonhan Confederacy of the Samhan period is included as part of early Gaya history.[2] One myth claims that six golden eggs descended from heaven, and after twelve days, they hatched into the first rulers of the six Gayas.
Due to the scarcity of texts from that time, little is known about daily life in Gaya. Like the other Korean kingdoms, they practiced Buddhism and shamanism. They lived in as many as eight walled cities, each independent and ruled by a king or chieftain. Wedged between two aggressive kingdoms—Baekje and Silla—Gaya struggled to maintain its independence. Though annexed in parts over the centuries, the last of the Gaya Confederation fell to Silla in 562 CE.
The controversies surrounding Gaya involve its relationship with Japan. Gaya’s proximity made it accessible by short sea voyages, and it supplied Japan with iron and harness parts. It also acted as a middleman in cultural exchanges with China. Many Koreans argue that much of Japanese culture originated in Korea. In response, some Japanese nationalists have claimed that early Japanese emperors colonized Korea, calling the region Mimana.
The Japanese chronicle Nihon Shoki, compiled in 720 CE, is the second-oldest Japanese historical text and is regarded as foundational. It covers Japan’s founding myths and imperial reigns but also describes relations with the Korean Peninsula, including with Gaya (referred to as Mimana or Imna). The text mentions delegations, military movements, and wars, indicating active interaction between Yamato-Wa (early Japan) and Korea.
In the 19th and 20th centuries, Japanese scholars claimed that Yamato-Wa actually controlled Gaya, interpreting Nihon Shoki passages about colonies to mean that Mimana was Gaya itself. Korean historians, however, strongly dispute this, especially since Japan used the claim to justify its 20th-century occupation of Korea, which Koreans remember as brutal.
Alternative theories have emerged. One North Korean scholar argued that Mimana was actually a Gaya settlement on the Japanese mainland, which—if true—would raise provocative questions about cultural ownership in Japan. Today, the most widely accepted theory among historians is that Mimana was likely a diplomatic outpost or embassy in Gaya, facilitating relations between Gaya and Japan. The debate, however, remains unresolved.
Unified Silla and the Golden Age of Buddhism
The Unified Silla Kingdom (668–935 CE) marked the peak of Buddhist culture in Korea. Buddhism flourished as a dominant force in society, shaping art, philosophy, and government. The state promoted Buddhism by building elaborate temples—often in the form of mandalas—for spiritual protection. Monks traveled to Tang China to study, returning with texts, doctrines, and practices, including new sects such as Pure Land Buddhism and Chan Buddhism (known later as Zen in Japan and Seon in Korea). Buddhism thus became central to Korea’s cultural development, inspiring temples, stupas, and sacred writings.
The unification of the Korean Peninsula under Silla came about through alliances and war. With Tang China’s aid, Silla defeated Baekje in 660 CE and Goguryeo in 668 CE. Yet inviting Tang forces into the peninsula proved risky: once victorious, Tang attempted to dominate the entire region. From 668 onward, Tang occupied large parts of Korea for nearly a decade.
Revolts broke out, especially in former Goguryeo lands, straining Tang control. In 675 CE, Tang forces defeated Silla in battle, but after Silla’s King Munmu offered apologies and tribute, Tang withdrew, distracted by rebellion elsewhere. Seizing the opportunity, Silla consolidated its control over the peninsula.
Still, the north remained outside Silla’s grasp. Balhae, a multiethnic kingdom, arose in the northern Korean Peninsula, northeast China, and parts of Mongolia, lasting from 668 to 926 CE. Its origins and identity remain somewhat mysterious, with competing claims from China, Russia, and Korea. For Koreans, Balhae represented the “Northern Dynasty,” while Silla was the “Southern Dynasty.”
Despite such complexities, Unified Silla fostered a strong sense of shared Korean identity. For many, it was the first time they felt they were truly one people.