Explore why the Mongol-Koryo invasions of Japan failed, how outdated samurai warfare was exposed, and why this event shaped centuries of Japanese fear toward Korea and Mongol power.👇
1. Samurai Warfare vs. East Asian Military Evolution
1.1. Ancient China’s Expansion and Internal War Patterns
China’s history shows a cycle: external conquest leads to internal warfare. Like the Spring and Autumn period evolving into the Warring States era, China's inability to expand quickly enough for its population and military strength led to fragmentation. Japan’s Sengoku period followed a similar internal war logic.
1.2. Archaic Samurai Tactics
Unlike Korea and China, ancient Japan had a primitive form of warfare. Samurai engaged in nanori—introducing themselves on horseback before engaging in ritual archery. Fights resembled sporting duels more than real war. Often, a match ended if someone bled or fell off their horse. This system lacked military realism.
1.3. Korean Peninsula’s Harsh Military Environment
In contrast, Korean states like Goguryeo faced constant multi-front threats—from Han commanderies, Chinese dynasties, northern nomads, and fellow Korean kingdoms. This intense pressure created advanced military technology and battle experience far beyond that of Japan. Korea’s warfare was shaped by brutal survival, not ritual.
1.4. Scale of Raids: Waegu vs. Silla Pirates
Late Goryeo faced powerful Japanese pirate fleets, yet never lost a major battle when top generals like Yi Seong-gye led. In contrast, when Silla sent only 2,500 pirates, Japan suffered so severely that parts of its islands became uninhabited—demonstrating how fragile Japanese defense was against organized foreign forces.
2. The Mongol-Koryo Invasions of Japan
2.1. The Campaign and Samurai Shock
The 1274 and 1281 invasions combined the Mongol Empire’s elite troops with Goryeo forces—seasoned through 30 years of Mongol resistance. When samurai attempted their usual nanori rituals, Mongol-Koryo troops simply shot them mid-speech. This stunned the Japanese, unaccustomed to real-time combat. Compared to encounters like the British vs. Zulu, this clash was even more one-sided.
With superior archery, coordination, and firepower, the invaders easily routed Japanese forces. The scale was such that the invaders camped, rested, and returned to battle at leisure—indicative of their overwhelming advantage.
2.2. The Myth of Kamikaze and Birth of Fear
Despite military superiority, storms (kamikaze, or "divine wind") destroyed much of the invasion fleets. The Japanese believed divine intervention saved them. This birthed the myth of kamikaze, later distorted into suicide attacks during WWII. “Mongol-Koryo” became synonymous with monsters in Japanese culture—Mukuri-Kokuri—names whispered to scare children for centuries.
Even atomic mushroom clouds were compared to “Mukuri-Kokuri arrows,” symbolizing deep-seated fear toward Korea and Mongolia.
2.3. Goryeo’s Reluctant Participation and Japan’s Resentment
Goryeo joined the invasions under Mongol coercion, knowing overseas conquests were economically unfeasible. Yet Japanese captured pirates reportedly said they came to “avenge Mukuri-Kokuri.” This bitterness later became the ideological seed of Japan’s Meiji-era Seikanron—the belief that Korea must be conquered to erase past humiliation.
This longstanding resentment influenced colonial policy and Japanese distrust toward Korea well into the 20th century.
2.4. Rewriting History: Kim Bang-gyeong’s Redemption
Goryeo commander Kim Bang-gyeong was later portrayed as a noble figure in Japanese novelist Inoue Yasushi’s epic. The story humanized Goryeo’s role, revealing that it had no desire to conquer Japan. For many Japanese readers, this was the first time learning that Korea had been dragged unwillingly into the invasions—softening centuries of hostility.
3. Collapse of the Kamakura Shogunate
3.1. Feudal Structure and Compensation Crisis
Samurai fought for land rewards, but the sea-born Mongol-Koryo invasions brought no spoils. Unlike internal wars where defeated domains could be redistributed, there was no land to reward after repelling an external threat. The Kamakura Shogunate could not compensate its warriors, triggering disillusionment, rebellion, and the eventual rise of the Ashikaga Shogunate through the Muromachi period.
3.2. From Invasion to Civil War
The Mongol-Koryo invasions occurred in 1274 and 1281. By 1392, Japan entered the Nanboku-chō (Northern and Southern Courts) period, with two emperors backed by rival warlords. Ultimately, the side aligned with the Muromachi Shogunate prevailed, setting the tone for another century of internal strife and weakened central control.
Conclusion: When Primitive War Met Professional Armies
The Mongol-Koryo invasions exposed Japan’s lack of real military preparation. Samurai warfare, built on ritual and hierarchy, collapsed in the face of disciplined, brutal, and advanced warfare. The shock reverberated for centuries, embedding deep psychological scars in Japanese national identity.
While the invasions failed due to storms, their impact reshaped Japan’s politics, perception of Korea and Mongolia, and even inspired some of its darkest wartime ideologies. Understanding this event highlights the dangers of mythologizing history and the importance of facing historical truths with clarity.
