50 years of conquest saw Mongol armies at the gates of Hungary, Persia, and along the Yangtze facing the last remaining Chinese resistance.
The Mongols thought they were invincible and with good reason. A succession of aggressive leaders started with Genghis Khan in 1211. This extended to their last truly expansionist ruler, his grandson Kublai Khan who died in 1294.
He transformed a small band of nomadic herdsmen into a vast army that unleashed like a flood across the Eurasian continent. He created the largest empire in human history to that point.
Yet, in their attempt to conquer fractious Japan, they found their limits.
Mongolian Battle and Conquer Tactics
From outward appearances, there was nothing special about the Mongols. They were excellent horsemen and on the open steppe, few could match their equestrian prowess or skill with the bow.
Their eventual armies numbered in the hundreds of thousands. But this did not reflect a massive population occupying the Mongolian grasslands.
Most of the Mongolian forces, especially after their early conquests, were not Mongolian. Peter Turchin estimates that actual Mongolian warriors made up less than 10% of most of these huge Mongolian armies. What set them apart was something far more intangible:
The Mongol army was a well-oiled social mechanism, capable of discipline and internal cohesion to the degree unknown in Europe since the Roman times. The Mongol armies deployed, advanced, and maneuvered in eerie silence. There were not even shouts of command because movements of the blocks of cavalry were governed by the flag signals from the standard bearers. At the right moment, the whole army suddenly charged, yelling and shrieking like demons. Such tactics were extremely unnerving to their adversaries. One of the favorite tricks used by the Mongols was the fake retreat, luring the unwary enemy into ambush and annihilation. Performing such maneuvers with a host of 100,000 called for precision timing and frictionless cooperationTurchin, p. 37
Mongolian forces were highly mobile. They appeared and reappeared unpredictably. They unnerved opponents who were used to frontal combat where two forces lined up against each other and superior strength determined the outcome.
Military history has shown repeatedly that flanking maneuvers, especially when coupled with psychological warfare, can break forces many times larger than your own. These were the tactics used by Hannibal at Cannae and Napoleon at Marengo and countless other victories.
Mongolians had this strategy baked into their military organization. They favored a decimal system of military organization with units ranging in size from 10 horsemen to 10,000. Each unit was capable of independent and coordinated action to take advantage of flanking opportunities.
This strategy had its limits, however. It was not effective when Mongolian forces encountered fortified places. These barriers brought out the other facet of their cooperation.
They were extremely inclusive of conquered people if they cooperated fully with their new masters. In such a way, they gained the technology and skills necessary to overcome fortified places.
However, the Mongols coupled this cooperative attitude with a brutal alternative. Once they had taken a few cities, they made a practice of slaughtering all their inhabitants.
When they approached a defended area, they offered the leaders a choice: either cooperate and be welcomed into the Mongolian Empire, or die to the last man, woman, and child.
How the Mongols Conquered an Empire
The initial regions they encountered were deeply divided and lacked strong centralized institutions. These smaller principalities often refused to cooperate. This allowed the Mongolians to make stunning progress through what is now Russia and Central Asia.
Once they hit more established societies in the Middle East, India, and China, however, their progress slowed considerably.
The Song Dynasty, which was forced south of the Yangtze River by their Jin rivals, held out the longest. Other holdouts included the kingdoms on the Korean peninsula, which had a long tradition of holding out against Japanese and Chinese invaders.
After subjugating the Jin in 1234, it would take another 45 years for them to overcome the Song in the south. The Korean kingdoms would take almost as long, only falling in 1269. In both cases, internal dynastic conflicts created diplomatic opportunities for the Mongolians to divide and conquer.
As they conquered these two states, the forces of Kublai Khan became aware of an island state just off the coast of Japan. Japan was rumored to have great wealth, making it an attractive target for plunder.
The Japanese had a long history of meddling in Korean politics, which further antagonized the Khan. This was the part of Asia closest to the home islands. They were friendly with the Song, who the Mongols were still fighting until 1279.
In 1268, he sent the first of several entreaties to the Japanese court in Kyoto. The terms of Japanese acquiescence were relatively mild.
As was their wont, the Mongols initially attempted to establish its strategic goal by diplomatic means, only resorting to military tactics when their terms and conditions were met with rejection.Choi and Yi, p. 190
The Japanese remained silent to these overtures in response.
The Emergence of Kamakura Bakufu in Japan
The reasons for this silence had deep roots in Japanese society. Japan existed for most of its history as a set of organized chaos. The mountainous nature of the many islands led to a decentralized system of governance.
While the emperor in Kyoto centralized control 600 years before the Mongol invasions, this control gradually degraded as the imperial court became dependent on local warlords. The emperor was nominally in charge (and divine). But the warlords were the ones who controlled taxation and the local militaries. There was no imperial army.
By the time of Kublai Khan’s embassies, the imperial court only exercised moral authority over the Kamakura military governors stretched throughout the country. The Japanese were aware of the threat that the Mongols posed through their friendly relations with the Song Chinese and various factions on the Korean Peninsula.
However, they could not exercise a coherent foreign policy because of the internal divisions within the country and the lack of effective centralized control, even over external relations.
Based on their experience in China, this would seem to offer a brilliant opportunity for the Mongol practice of divide and conquer. However, what the Russian and Central Asian principalities lacked over the Japanese was a sense of ethnic superiority.
Whatever divided the Japanese internally was counterbalanced by a sense that collectively the Japanese, and by extension, their emperor, were a divine people. Kublai’s suggestion in his initial letter to the imperial court in 1267 that he was superior to the Japanese emperor was therefore a great affront to national pride and rallied support for resisting any attempts at invasion.
The First “Invasion”
After repeated failed overtures to the court in Kyoto, Kublai thought a show of force was necessary to cow the Japanese into submission. This followed the pattern well-established by Mongol forces to start with a demand for submission and, failing that, a show of military strength.
The problem that the Khan faced was that the Mongols had no experience operating across seas. Their experience in naval warfare against the Song had consisted almost entirely of riverine warfare.
The Mongols had shown themselves to be innovative in this. They introduced trebuchets to floating platforms, for instance. But fighting on the Yangtze and its tributaries differed completely from crossing 100 miles of open water in the Tsushima Strait.
After consolidating his power in Korea and enlisting the effort of Korean shipbuilders and seamen, Kublai ordered his armies to cross the straits to Japan in late 1274. This attack was ill-timed because of the weather.
While typhoon season was over, storms were still a frequent occurrence as the winter approached. The Mongols never had to reckon with weather in this way and their Korean vassals either would not or did not warn them of the dangers of Mother Nature.
The expedition comprised 900 ships, 30,500 warriors, and 6,700 sailors manning the ships under three Mongol leaders, Hindu, Hong Dagu, and Liu Feng (Rhode). Like Caesar’s landing in Britain 1300 years before, there is a lot of debate about the goals of the expedition.
The Mongols left few written records and most accounts of their actions were written by outsiders. Based on their past actions, however, the Mongols probably expected to meet fractured resistance from the Japanese and were looking for targets of opportunity.
Kublai also wanted to cow the imperial court in Kyoto into submitting to his earlier demands.
The Mongol forces quickly overwhelmed the small garrisons of the Tsushima islands and slaughtered many of the inhabitants. Their next target was Hakata Bay, the site of the modern city of Fukuoka, and the provincial capital of Dazaifu.
Kublai was right about one thing. The Japanese were divided and the local Bakufu (military governor) could only muster forces a fraction of the size of the Mongol army. Mongol troops brushed the samurai and infantry defending the beach at Hakata Bay aside with relative ease and made for Dazaifu.
However, the samurai defended the Mizuki Castle. They guarded the approaches to the city, against the Mongol forces, who lacked much of the equipment that they used in similar campaigns in China.
After less than a month, the Mongol forces withdrew, having done minimal damage and suffering significant casualties. Most deaths were caused by the rough November weather rather than by Japanese action.
This fleet’s withdrawal is often explained by the appearance of a typhoon. However, Kamada and Kanemitsu (2013) argue that this was impossible that late in the year.
Whatever the reason for the withdrawal, the limited success of forces was not the message that Kublai wanted to send and he punished his generals for their failure. In 1275, he prepared for a follow-up attack.
However, the final stages of the war against the Song Empire distracted him and ate up the resources necessary for a follow-on attack. In the meantime, he sent additional embassies to the Japanese court. This time, the Japanese response was more decisive. All the emissaries were beheaded.
The 1281 Invasion Attempt
In 1279, the Song finally fell to Mongol attacks. This left Kublai a free hand to turn his attention once again to the insolent Japanese.
The Mongols gained additional naval experience and resources from their last campaigns against the Song. They advanced down the coast from Shanghai in a series of naval battles. Chinese seamen and shipwrights in coastal dockyards added to their pool of resources.
This time, the attack was to come from two directions. One prong was to follow the track of the 1274 attack. The other was to cross from China and meet up at Iki Island, off the shore of the southernmost Japanese island of Kyushu.
The Mongol commanders once again selected Hakata Bay as a landing site. This time, the attack was to start much earlier in the year, in May.
Accounts differ, but some estimates put the size of each prong at 100,000 warriors carried by thousands of ships. This is comparable to the force the Allies landed in Normandy in 1944.
The Mongols learned the logistic challenges of keeping their armies in the field across bodies of water. They included ample supply ships to meet both the food and weapons needs of their troops once landed.
Because of the death of the southern commander, the northern prong set off first. Retracing the steps of the first expedition, they took Tsushima in early June. Captives there told the Mongols that Hakata Bay was still undefended.
This was not true.
In the years after 1274, the local Bakufu constructed a 15-mile-long stone wall along the shoreline. This wall was ramped and allowed the samurai to ride their horses up the wall, fire their arrows, and then retreat to reload. This tactic resembled the hull-down tactics used by armored forces in the 20th century and it had a similar effect.
The Mongol forces were trapped along a narrow strip of beach and subjected to attack from a practically invulnerable enemy. The samurai, unlike in the first raid, suffered few casualties.
After this aborted attack, the northern force withdrew and awaited the southern forces’ arrival at Iki. The ships were moored offshore, laden with troops. The Japanese craft engaged in hit-and-run attacks to weaken the Mongol forces. These attacks continued even after the southern force arrived and the combined fleet moved to Imari Bay, beyond the length of the new wall.
So far, like in 1274, the Mongol forces suffered significant casualties, with little to show for it. They began preparations for a major landing in mid-August. By this point, the troops were exhausted, and the landings progressed slowly. Most of the Mongol forces were aboard ships for months and food supplies were running low.
On the other side, however, there were equal problems. Despite the heroics of the Japanese fleet, the ground forces assembled to meet the oncoming attack were inadequate. Many Japanese leaders were preparing for the worst.
It was at this point that the weather intervened again, this time decisively. Just as the Mongol landings were getting underway, a typhoon blew up from the south. This drove hundreds of their ships, handled by inexperienced crews, onto the rocks.
Four days later, the Mongol commander Fan Wenhu sailed away, leaving at least 100,000 men dead or stranded. The Japanese killed 20,000-30,000 shipwrecked survivors. The rest died in the storm.
Kublai Khan died in 1294. With his death, any ideas of invading Japan vanished as his successors struggled to rule their gains in China and Korea. The Mongolian dynasty there only lasted another 50 years, falling to the Mings in the 1350s.
In Japan, the successful defense ironically weakened central control even further. The fighters who defended Kyushu demanded payment. The impoverished court was unable or unwilling to provide this.
The storm made it clear to many that Japan was divinely protected. This became part of the national mythology and was enshrined into the term “divine wind” or kamikaze.
This word became famous to the Western world 550 years later when Japanese pilots attempted to replicate the miracle of the kamikaze by crashing their planes into American and British ships attacking Japan in 1945.
Andrade, Tonio, The Gunpowder Age: China, Military Innovation, and the Rise of the West in World History (Princeton: Princeton University Press, 2016).
Choi, Lyong and Sang Hun Yi, “Forced Self-Reliance: The Kamakura Bakufu Defense against the Mongol Invasion of Japan,” Journal of Interdisciplinary History, 52.2 (Autumn 2021), pp. 177-196.
Kamada, M. and S. Kanemitsu, “Did the Kamikaze Blow? A Dynamic History” Kayanomori 19 (2013), pp. 1-5.
Rhode, Grant, “Mongol Invasions of Northeast Asia, Korea, and Japan” retrieved 4/29/23 from https://www.asianstudies.org/wp-content/uploads/china-global-history-and-the-sea-case-study-guide.pdf
Turchin, Peter, War and Peace and War: The Rise and Fall of Empires (New York: Penguin, 2007)