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  • Writer's pictureBruce Boyce


"Now it happened one day that such a gale was blowing from the north that

the troops declared that, if they did not get away, all their ships would be

wrecked. So they all embarked and left the island and put out to sea. And let

me tell you that when they had sailed about four miles, the gale began to

freshen and there was such a crowd of ships that many of them were smashed

by colliding with one another."

Marco Polo, Book of the Marvels of the World, c.1300

The Mongol invasions into central and eastern Europe left an indelible mark on the psyche of Europeans for generations. During the 13th century, East Asia experienced a similar significant transformation driven by the nomadic tribes of the north, united under the leadership of Genghis Khan, leading to the establishment of the Mongol Empire. The Mongol conquest of China spanned 70 years, from Genghis Khan to Khubilai Khan's establishment of the Yuan (Mongol) dynasty. This conquest, the most prolonged military action in the creation of the Mongol empire, marked a conceptual shift from nomadism to imperialism. After the siege of Kaifeng in 1232 ended the Jin dynasty, the Mongols pressed forward against the Southern Song. Hindered by obstacles and facing naval challenges, the Mongols captured Song ships, realizing the need for a navy. The prolonged Mongol siege of Xiangyang and subsequent battles led to the fall of the Song capital at Hangzhou in 1276. A sea battle in 1279 eliminated the last remnants of the dynasty.

Kublai Khan

Against the backdrop of Chinese conquests, the Mongols invaded Korea in 1231, and the Goryeo dynasty's royal court sought refuge on Ganghwa Island. This marked the first time in Mongol conquest history that they faced a barrier of the sea, hindering their aim to surrender the Goryeo monarch. Political changes in Korean politics in 1258 favored the Mongols, as the resistance from Ganghwa, controlled by an anti-Mongol faction, weakened. The king took personal control and sent hostages as a peace gesture but faced opposition in the 'Rebellion of the Three Patrols.' The Korean royal family called Mongol troops in to overthrow the rebels in 1270, leading to the insurgents fleeing to Jeju Island. A strategic marriage alliance in 1273 solidified the Mongols as overlords. Within a year, the Korean king witnessed the commandeering of his country's soldiers and naval resources by the Mongols for their ambitious maritime project—the invasion of Japan.

Khubilai Khan sought to extend his hegemony to Japan in 1271. However, Japan had maintained a policy of isolation for over 70 years, refraining from official diplomatic relations with China and Korea. The motivation behind Khubilai Khan's invasion of Japan in 1274 remains a subject of historical speculation. One perspective, as highlighted by the Venetian merchant and traveler Marco Polo, suggests that the allure of Japan's immense gold reserves played a significant role. Japan was known for its gold production, dating back to its discovery in 749. Japan's reputation abroad was bolstered by its ability to send large quantities of gold to China during the Song dynasty. The legend of Japan as a "land of gold" may have influenced Khubilai Khan's decision to conquer the island. However, some considered it part of the Mongol emperor's ambition for world dominance, a viewpoint supported by the king of Korea. Additionally, Japanese officials believed that the Mongols sought to exploit Japan's military prowess for future conquests, starting with the Southern Song in China.

Kublai Khan's letter to Japan

Kublai Khan at first instigated a diplomatic approach. The Mongol diplomatic effort against Japan was facilitated through pressure on the Korean court, using Korea as a messenger. This approach reinforced Mongol control over Korea and, if peaceful means failed, positioned a submissive Korea as a base for invasion. He sent a letter to Japan via an ambassador, Zhao Liangbi, in 1268. The Great Khan recognized Japan's leader as the 'king of Japan' and wished for friendly relations while subtly demanding tribute. Despite these diplomatic efforts, Japan, under the rule of the Kamakura Shogunate led by Hojo Tokimune, rebuffed the Mongol overtures.

While the overall tone of Kublai’s letter may have seemed mild, references to the 'king of Japan' compared to the 'emperor of the Great Mongols' were perceived as insulting by the Japanese imperial court. Chinese scholars pointed out that certain phrases in the letter were commonly used between equals rather than from superiors to inferiors, but the status-conscious recipients interpreted it differently. The invitation to 'establish friendly relations' was considered provocative, hinting at a 'tributary relationship' that Japan had adamantly declined for centuries. Japan already maintained a positive informal relationship with the Southern Song, fostering a steady flow of goods and culture between Japan and China. Consequently, there was no incentive to appease the Mongol ruler or betray existing friendships. The last paragraph of the letter implied, at the very least, the threat of war. The impending danger was sensed early, leading to the earliest recorded prayers for protection against the Mongols. Emperor Kameyama's chamberlain issued an edict in 1271, expressing concern about the Northern Barbarians' plot to conquer Japan and praying for peace.

The Japanese response displayed a lack of subtlety, possibly influenced by their limited experience in international relations after a period of isolation. The bias of their principal contact with mainland Asia, the Southern Song, and the negative opinions exiled Chinese Zen Buddhist monks held toward the Mongol conquerors might have contributed to Japan's rejection of the diplomatic advances.

The mention of warnings from the Korean court and the veiled threat in Kublai's letter prompted Japan to react in preparation for a possible invasion. Samurai were mobilized and placed under the command of local shugo ('constables'). The orders were specific, directing samurai families like Koshiro and Shodai to defend against the Mongols and protect their holdings in Kyushu. The mobilization order initially focused on Kyushu until 1274, when samurai from western Honshu were also called for.

In the early days of November 1274, Kublai Khan assembled a formidable fleet of around 800-900 ships and launched an invasion from Korea to Japan. The fleet carried an army comprising of Mongols and conscripted Chinese and Koreans, totaling between 16,600 and 40,000 men. The initial targets were Tsushima and Iki Islands, which were plundered despite valiant resistance from Japanese defenders. The defensive efforts, particularly at Hinotsume castle on Iki, proved brave, but the lack of reinforcements led to the castle’s fall. Subsequently, the invasion fleet made stops at Takashima Island and the Matsuura peninsula before landing in Hakata Bay on November 19. Although the Japanese had anticipated this location, their defense force, numbering between 4,000 and 6,000 men, faced challenges against the Mongols' superior numbers and weaponry.

The Mongols' military success was attributed to dynamic battlefield strategies, disciplined cavalry, and effective use of weapons like armor-piercing crossbows and poisoned arrows. Gunpowder warfare made its early appearance outside of China. One technological innovation of that time was using explosive bombs, referred to as "thunder crash bombs" in Chinese. These bombs were launched from catapults, causing considerable damage to enemy soldiers. While illustrations of these bombs are present in the Japanese Mongol Invasion scrolls, historians have argued that these depictions were added in the 18th century and shouldn't be considered eyewitness representations. However, subsequent archaeological discoveries have supported the existence of bombs in the Mongol invasion's arsenal. Multiple bomb shells, containing gunpowder and packed with scrap iron, were found in an underwater shipwreck off the shore of Japan by the Kyushu Okinawa Society for Underwater Archaeology. Additionally, there are indications that the Mongol forces may have utilized cannons during the invasion. Historical texts, such as the Nihon Kokujokushi from around 1300, mention "huo tong" or fire tubes at the Battle of Tsushima in 1274.

Gunpowder bombs recovered from shipwrecks

The Mongol soldiers introduced unfamiliar tactics, advancing on foot in large groups with shields, drums, and noise. This disrupted traditional Japanese fighting techniques, challenging small warrior bands and their sharpshooting traditions. Unaccustomed to mass troop movements, the Japanese operated in small groups led by mounted samurai and infantry armed with curved-bladed polearms. Despite disadvantages, the samurai's iron plate, leather armor, and long sharp swords provided some advantages. The Japanese defenders, despite some individual acts of courage, were forced back by the Mongols.

Mongol armor

The Mongols burned Japanese dwellings but chose not to spend the night on shore, returning to their ships. Various reasons have been speculated, including supply problems, the death of Mongol general Liu Fuxiang by a samurai's arrow, or the mission being a reconnaissance for a more extensive invasion. Regardless, the invaders withdrew into the bay on November 20, a decision that proved fateful. Reports suggest a severe storm struck, killing a significant portion of the Mongol army and damaging the fleet. Forced to withdraw back to Korea, the invasion of 1274 ended with the Mongols facing unforeseen challenges, including the forces of nature. The Japanese perceived it as a victory, attributing divine protection to a change in wind direction.

In 1275, Kublai Khan opted to try diplomacy once more and sent another embassy, demanding tribute. However, the shogunate's response was even more dismissive, leading to the beheading of the Mongol ambassadors on a beach near Kamakura. Unfazed by this, Kublai Khan persisted and dispatched a second embassy in 1279. Unfortunately, the messengers met the same fate as their predecessors. Recognizing that force might be the only means to bring Japan into the Mongol Empire, Kublai Khan set his sights on a potential second invasion. However, his attention was diverted by campaigns in southern China against the Song, delaying any immediate action against Japan for two more years.

Meanwhile, Japan had been anticipating an invasion since 1274. In response, preparations were made, including keeping the army on standby, constructing fortifications, and erecting massive stone walls around Hakata Bay in 1275. These walls, measuring 19 kilometers long (12 miles) and up to 2.8 meters in height (9 feet), featured sloped inner sides for horse-mounted archers and sheer outer facings. Having learned from the previous invasion, Japan was now much more prepared for any potential second incursion.

Kublai Khan's second invasion fleet marked a significant escalation in size compared to the first, consisting of 4,400 ships and around 100,000 men, a mix of Mongol, Chinese, and Korean warriors. The force for the invasion was significantly augmented, including criminals whose death sentences were commuted in exchange for serving in the army. Even those in mourning for their parents were enlisted after 50 days. The acquisition of the Song navy played a crucial role in bolstering this formidable force. Drawing from the lessons of the failed 1274 attempt, the strategy emphasized the need to pacify Tsushima and Iki before attempting a landing at Hakata. The planned 1281 assault indicated the Mongols' intention to permanently occupy Japanese land.

Samurai armor

The Eastern Route Army set sail from Korea on May 22, 1281. Tsushima was attacked on June 9, and Iki on June 14. The Eastern Route Army was supposed to wait for the Southern Route Army but decided to invade mainland Japan on their own, attacking Hakata Bay on June 23. The invaders also split their forces, attacking the province of Nagato on June 25, causing minimal damage. Ultimately, the samurai defending Nagato drove the Mongols off.

While Nagato was under attack by one detachment, the rest of the Eastern Route Army engaged in a fruitless operation at Hakata Bay. The Japanese had anticipated the attack on Hakata Bay, and their defenses proved successful. The defensive wall along the shore was crucial, preventing the Mongols from establishing a position. Although some Mongol craft came ashore, they faced volleys of arrows from the wall, hindering their progress. Unable to land, the Mongols occupied Shiga and Noko islands in the bay and prepared for raids against Hakata. Samurai led night attacks and daring raids against Mongol ships. They engaged in hand-to-hand combat, often boarding Mongol ships at night or using makeshift bridges. The resistance ultimately drove the Mongols back to Iki Island, marking the end of the invasion in Hakata Bay.

The pacified Southern Song armada, comprising 100,000 men on 3,500 ships, arrived in Japanese waters after sailing from south of the Yangtze. The fleets from Korea and Iki connected, and they set their sights on the island of Takashima, west of Hakata, separated by Imari Bay. A fierce sea battle took place near Takashima on August 12. Surprisingly, there are limited Japanese accounts of this battle. The Japanese retreated at dawn. The small Japanese warcraft was deemed no match for the Mongol ships, causing widespread fear. The Japanese emperor sought divine intervention by visiting the Hachiman Shrine. Hachiman was the Shinto God of War. The emperor implored for the country's salvation in exchange for his own life. The imminent threat of a decisive attack on Hakata and a successful invasion of Japan loomed large.

However, once again, nature intervened as a typhoon on August 14 wreaked havoc. The enduring image etched in history is that of hundreds of wrecked ships in Imari Bay, a consequence of the typhoon. This event, chronicled in the Travels of Marco Polo, marked the first Japanese historical event to reach Europe. The gale, fueled by north winds, struck the Mongol fleet as it sailed about four miles, causing collisions and devastation among the ships, leading to the ultimate abandonment of the invasion. The storm, later named "kamikaze" or divine winds, was seen as a response to the Japanese appeal to Hachiman for protection against a numerically superior enemy.

Typhoon destroying Mongol fleet, 19th century painting

The poorly constructed Mongol ships revealed through modern marine archaeology, played a role in their demise. Weak mast steps and rushed construction, driven by Kublai's urgency to assemble the fleet quickly, contributed to their lack of seaworthiness. Additionally, the defensive measure of lashing large ships together using chains proved fatal in the face of the typhoon. Japanese interpretations credited the victory to samurai heroism and divine intervention. The news brought joy to the imperial, seen as evidence of divine recognition and a call for piety.

In the historical context of Japan, the mythological significance of the Mongol invasions evolved over time, gaining increased importance. A notable development observed in the literature of subsequent centuries was the heightened use of the expression "shinkoku," designating Japan as the 'land of the gods' and portraying it as a uniquely protected land. This concept was closely linked to the growing polarization between the Japanese warrior and the demonized foreigner. The Mongol invasions left a lasting impact on Japan's perception of foreign threats. The defeat of the foreign invader, particularly highlighted by Hideyoshi's invasion of Korea in 1592, created a heightened fear of foreigners. This expedition mirrored the course of the Mongol invasion in the opposite direction and might have been perceived by some participants as revenge for the earlier incursion.

Even as late as 1853, a year before Japan opened its doors after three centuries of seclusion, prayers were offered for the subjugation of foreigners upon sighting their ships in Japanese waters. These prayers were rooted in curses originally used against the Mongol invaders. The association between the defense of Japan and the repulsion of the Mongol invasions persisted, evident in the events of 1945. During the imminent risk of foreign invasion, the last-ditch stand by suicide pilots, known as kamikaze, was carried out in both spirit and name, firmly linking the defense of Japan to the perceived finest hour during the Mongol invasions.


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