The of 1274 and 1281 were major military invasions and conquests undertaken by Kublai Khan to take the Japanese islands after the capitulation of Goryeo (Korea). Despite their ultimate failure, the invasion attempts are of macrohistorical importance, because they set a limit on Mongol expansion, and rank as nation-defining events in Japanese history. The Japanese were successful, which was helped by the Mongols losing up to 75% of their invading troops and supplies both times on the oceans because of huge storms. The invasions are referred to in many works of fiction, and are the earliest events for which the word kamikaze, or "divine wind", is widely used. In addition, with the exception of the Occupation of Japan at the end of World War II, these failed invasion attempts are the closest Japan has come to being invaded within the last 1500 years.

Background

After a series of Mongol invasions from 1231 to 1259, the Goryeo Dynasty of Korea signed a treaty in favor of the Mongols and became a Mongolian vassal. Kublai was declared Great Khan of the Mongol Empire in 1260 (though not widely recognized by the Mongols in the west) and established his capital at Dadu (Beijing) in 1264. Japan at the time was ruled by the Shikken (Shogunate Regents) of the Hōjō clan, who had intermarried with and wrested control from the Shogun of the Kamakura Shogunate after his death in 1203. The inner circle of the Hōjō had become so preeminent that they no longer consulted even the Hyōjō (評定) (the council of the shogunate of the Shogun), nor the Imperial Court of Kyoto, nor their vassals (gokenin), and made their decisions in their private meetings at their residences (寄合 yoriai).

Contact

290px|thumb|Letter from Kublai Khan to the Emperor of Japan, written in lingua franca in East Asia at the time), dated 8th Month, 1266. Now stored in Todai-ji, Nara, Japan./" class="wiki">Classical Chinese (the lingua franca in East Asia at the time), dated 8th Month, 1266. Now stored in Todai-ji, Nara, Japan.
In 1266, Kublai Khan dispatched emissaries to Japan, with a letter saying:
Kubilai basically demanded Japan to become a vassal and send tribute under a threat of conflict. However, the emissaries returned empty-handed.

A second set of emissaries were sent in 1268, returning empty-handed like the first. Both sets of emissaries met with the Chinzei Bugyō, or Defense Commissioner for the West, who passed on the message to Shikken Hōjō Tokimune, Japan's ruler in Kamakura, but also to the Emperor in Kyoto.

After discussing the letters with his inner circle, there was much debate as to what to do, but Tokimune had his mind made up; he had the emissaries sent back with no answer. They re-sent emissaries time and time again, some through Korean emissaries, and some by Mongol ambassadors in March 7, 1269; September 17, 1269; September, 1271; and May, 1272 - each time not even being permitted to land in Kyushu. The Imperial Court suggested surrender out of overwhelming fear, but really had no say in the matter since its marginalization after losing the Jōkyū War.

The Kamakura shogunate under Tokimune (Bakufu) ordered all those who held fiefs in Kyūshū (the area closest to Korea, and thus most likely to be attacked) to return to their lands, and forces in Kyūshū moved west, further securing the most likely landing points. After acknowledging its impotence, the Imperial Court led great prayer services, and much government business was put off to deal with this crisis.

First invasion

The Khan was willing to go to war as early as 1268 after having been rebuffed twice, but found that his empire did not have the resources to provide him with a sufficient navy at that time. With the Mongol entry into the Korean court by marriage of the Korean crown prince to Kublai Khan's daughter, a mass construction of ships began in Korea's south-eastern shores while continuing to demand surrender.

Kublai Khan founded the Yuan Dynasty in 1271. In 1272, Chungnyeol offered counsel to Kublai Khan. According to Goryeosa,
Japan is yet to the know world is hallowed. So dispatch emissaries and convey our military power to Japan. Battle ships and military rations are well prepared. If you appoint me, I encourage you to the extent of my power. Goryeosa 『高麗史』世家巻第二十七 元宗十三年 三月己亥（March,11,1272） 「惟彼日本 未蒙聖化。 故發詔使 繼糴軍容 戰艦兵糧 方在所須。儻以此事委臣 庶幾勉盡心力 小助王師」 According to History of Yuan, King of Goryeo ask Kublai Khan for conquering Japan. I am building 150 ships and encourage your conquest of Japan. History of Yuan 『元史』 卷十二 本紀第十二 世祖九 至元十九年七月壬戌（August,9,1282）「高麗国王請、自造船百五十艘、助征日本。」thumb|left|250px|A stone defense wall in Fukuoka/" class="wiki">Hakata, now Fukuoka
Finally, in 1274, the Yuan fleet set out, with an estimated 15,000 Mongol & Chinese soldiers and 8,000 Korean warriors, in 300 large vessels and 400-500 smaller craft, although figures vary considerably depending on the source. They ravaged the islands of Tsushima and Iki, including piercing the hands of women and hanging them on their boats. They landed on November 19 in Hakata Bay, a short distance from Dazaifu, the ancient administrative capital of Kyūshū, but really just a small outpost. The following day brought the Battle of Bun'ei (文永の役), also known as the "Battle of Hakata Bay".
thumb|150px|right|The Mongol fleet destroyed in a typhoon, ink and water on paper, by Kikuchi Yōsai, 1847
The Japanese were inexperienced in managing such a large force (all of North Kyūshū had been mobilized), and the Mongols made significant initial progress. It had been approximately 50 years since the last major combat event in Japan (Go-Toba's adherents in 1221), leaving not a single Japanese general with adequate experience in moving large bodies of troops. In addition, the style of warfare that then was customary within feudal Japan involved man-to-man duels of sorts, even on large battlefields. The Mongols possessed foreign weapons which included superior long-range armaments ("proto-grenades"), and easily had the upper hand in land combat. The Japanese force at Hakata Bay needed time to await the arrival of reinforcements, with which they would be able to overwhelm the Mongol invaders. Around nightfall, a severe storm caused the Mongol ship captains to suggest that the land force re-embark on the sailing vessels in order to avoid the risk of being marooned on Japanese soil. By daybreak, only a few ships had not set out to sea. Those that had met their doom at nature's hand. Different accounts offer casualty reports that suggest 200 Mongol ships were lost. However, Japanese small boats were much swifter and more maneuverable than Mongol ships, and the Japanese were able to board the remaining Mongol ships. Mongols without their long-range land weapons and armor, once in hand-to-hand combat, stood little chance against the disciplined samurai and their tachi.

Meanwhile back in Kamakura, Tokimune was overcome with fear when the invasion finally came, and wanted to defeat cowardice, so he asked Bukko (his Zen master) for advice. Bukko replied he had to sit in meditation to find the source of his cowardice in himself. Tokimune went to Bukko and said: "Finally there is the greatest happening of my life." Bukko asked, "How do you plan to face it?" Tokimune screamed "Katsu!" ("Victory!") as if he wanted to scare all the enemies in front of him. Bukko responded with satisfaction: "It is true that the son of a lion roars as a lion!" Since that time, Tokimune became instrumental in the spreading of Zen Buddhism and Bushido in Japan among the samurai.

After the invasion, allied fleets returned to their homeland. The Goryeo general Kim Bang-gyeong paid tribute to the king and queen of Goryeo with 200 boys and girls for slaves.

Developments leading to the second invasion

thumb|300px|Defensive wall at HakataStarting in 1275, the Kamakura shogunate (Bakufu) made increased efforts to defend against the second invasion which they thought was sure to come. In addition to better organizing the samurai of Kyūshū, they ordered the construction of forts and a large stone wall, and other defensive structures at many potential landing points, including Hakata Bay, where a two meter high wall was constructed in 1276. Religious services increased and the Hakōzaki shrine, having been destroyed by the Yuan forces, was rebuilt. A coastal watch was instituted and rewards were given to some 120 valiant samurai. There was even a plan for a raid on Korea to be carried out by Shōni Tsunesuke, a general from Kyūshū, though this was never executed.

After the failed invasion, Kublai Khan was tired of being ignored and not being allowed to land, so five Yuan emissaries were dispatched in September 1275 and sent to Kyūshū, refusing to leave without a reply. Tokimune responded by having them sent to Kamakura and then beheading them. The graves of those 5 executed Yuan emissaries exist to this day in Kamakura at Tatsunokuchi. Then again on July 29, 1279, 5 more Yuan emissaries were sent in the same manner, and again beheaded, this time in Hakata. Expecting another invasion, on Feb 21, 1280, the Imperial Court ordered all temples and shrines to pray for victory over the Yuan.

Second invasion

thumb|left|300px|Japanese samurai boarding Yuan ships in 1281In the spring of 1281, the Mongols sent two separate forces; an impressive force of 900 ships containing 40,000 Korean, Chinese, and Mongol troops set out from Masan, while an even larger force of 100,000 sailed from southern China in 3,500 ships. The Ministry for Conquering Japan's plan called for an overwhelming coordinated attack from the combined imperial Yuan fleets.The Chinese fleet of the Yuan was delayed by difficulties in provisioning and manning the large number of ships they had. Their Korean fleet set sail, suffered heavy losses at Tsushima, and turned back. In the summer, the combined Korean/Chinese fleet took Iki-shima, and moved on to Kyūshū, landing at a number of separate positions. In a number of individual skirmishes, known collectively as the Battle of Kōan (弘安の役), or the Second Battle of Hakata Bay, the Mongol forces were driven back to their ships. The Japanese army was again heavily outnumbered, but had fortified the coastal line, and was easily able to repulse the auxiliaries that were launched against it. The now-famous kamikaze, a massive typhoon, assaulted the shores of Kyūshū for two days straight, and destroyed much of the Mongol fleet.

Furthermore, it is now believed that the destruction of the Mongol fleet was greatly facilitated by an additional factor. Most of the invasion force was composed of hastily-acquired flat-bottomed Chinese riverboats and ships built in Goryeo of a similar type. According to Goryeosa, Southern Song type ships were too costly and their construction was too slow, so the traditional types were constructed. Such ships (unlike ocean-going ships, which have a curved keel to prevent capsizing) were difficult to use on high seas, let alone during a massive typhoon. It is also speculated that the Chinese who built the boats and ships might have intentionally made inferior boats because they disliked their Mongol rulers.

Significance

From a military perspective, the failed invasions of Kublai Khan were the first of only two instances (the other being the Japanese invasion of Korea in 1592) where the samurai would fight foreign troops rather than amongst themselves. It is also the first time samurai clans fought for the sake of Japan itself instead of more narrowly defined clan interests. The invasions also exposed the Japanese to an alien fighting style which, devoid of the single combats that characterized traditional samurai combat, they saw as inferior. This difference is noted in the Hachiman Gudōkun:

The Mongol method of advances and withdrawals accompanied by bells, drums and war cries was also unknown in Japan, as was the technique of Mongolian archers, which involved shooting arrows en masse into the air rather than long-ranged one-on-one combat. Besides national boundaries, the Zen Buddhism of Hojo Tokimune and his Zen master Bukko had gained credibility, and the first mass followings of Zen teachings among samurai began to flourish. This also marks the first use of the word kamikaze ("Divine Wind") It also perpetuated the Japanese belief that they could not be defeated, which remained an important aspect of Japanese foreign policy until the end of the Second World War. The invasions were also the only time that enemy nations would mount an invasion of any of the main four islands of Japan. The failed invasions also demonstrated a weakness of the Mongols - the inability to mount naval invasions successfully. (see also Mongol invasions of Vietnam).

As Paul K. Davis wrote, "The destruction of the Mongol fleets guaranteed Japanese independence, yet created a power struggle in the Japanese military government that led to the military’s dominance over the emperor."

Popular culture

• In the Mongol Invasion expansion for the PC game Shogun: Total War, the campaign included postulates an invasion which was not cut short by the typhoons.

• Age of Empires II, another PC game, also included missions relating to the Mongol invasions.