Mongol invasions of Japan

The Yuan invasion force set off from Korea on 2 November 1274. Two days later they began landing on Tsushima Island. The principal landing was made at Komoda beach near Sasuura, on the northwestern tip of the southern island. Additional landings occurred in the strait between the two islands of Tsushima, as well as at two points on the northern island.[11] The following description of events is based on contemporary Japanese sources, notably the Sō Shi Kafu, a history of the Sō clan of Tsushima.

At Sasuura, the invasion fleet was spotted offshore, allowing the deputy governor (jitodai) Sō Sukekuni (1207–74) to organize a hasty defense. On that day, the shrine to Hachiman caught fire, which would have been an omen of bad luck, but Sukekuni interpreted it as an omen of warning.[11]

With 80 mounted samurai and their retinue, Sukekuni confronted an invasion force of what the Sō Shi Kafu describes as 8,000 warriors embarked on 900 ships.[12] The Mongols landed at 02:00 in the morning on 5 November, and ignored the Japanese negotiation attempts, opening fire with their archers and forcing them to retreat. The fight was engaged by 04:00.[12] The small garrison force was quickly defeated, but according to the Sō Shi Kafu, one samurai, Sukesada, cut down 25 enemy soldiers in individual combat.[13] The invaders defeated a final Japanese cavalry charge around nightfall.[13][12]

After their victory at Komoda, the Yuan forces burnt down most of the buildings around Sasuura and slaughtered most of the inhabitants. They took the next few days to secure control of Tsushima.[12]

The Yuan fleet departed Tsushima on 13 November and attacked Iki Island. Like Sukekuni, Taira no Kagetaka, the governor of Iki, gave a spirited defence with 100 samurai and the local armed populace before falling back to his castle by nightfall. The next morning, Yuan forces had surrounded the castle. Kagetaka snuck out his daughter with a trusted samurai, Sōzaburō, on a secret passage to the shore, where they boarded a ship and fled for the mainland. A passing Mongol fleet shot arrows at them and killed the daughter but Sōzaburō managed to reach Hakata Bay and report Iki's defeat.[14]

Kagetaka made a final failed sortie with 36 men, 30 of whom died in battle, before committing suicide with his family.[15] According to the Japanese, the Mongols then held down the women and stabbed through their palms with knives, stripped them naked, and tied their corpses to the sides of their ships.[16]

The Yuan fleet crossed the sea and landed in Hakata Bay on 19 November, a short distance from Dazaifu, the ancient administrative capital of Kyūshū. The following day brought the Battle of Bun'ei (文永の役), also known as the "First Battle of Hakata Bay".

Conlan argues that the History of Yuan's account of the battle suggests that both the Japanese and Yuan forces were of similar size. Conlan estimates that both armies numbered around 3,000 each (not including the Yuan sailors) during this battle[17] while Japanese historians estimate 6,000 defenders on the Japanese side.[18] The Japanese forces, being inexperienced with non-Japanese tactics, found the Mongol army perplexing. The Yuan forces disembarked and advanced in a dense body protected by a screen of shields. They wielded their polearms in a tightly packed fashion with no space between them. As they advanced they also threw paper and iron casing bombs on occasion, frightening the Japanese horses and making them uncontrollable in battle. When the grandson of a Japanese commander shot an arrow to announce the beginning of battle, the Mongols burst out laughing.[19]

The commanding general kept his position on high ground, and directed the various detachments as need be with signals from hand-drums. But whenever the (Mongol) soldiers took to flight, they sent iron bomb-shells (tetsuho) flying against us, which made our side dizzy and confused. Our soldiers were frightened out of their wits by the thundering explosions; their eyes were blinded, their ears deafened, so that they could hardly distinguish east from west. According to our manner of fighting, we must first call out by name someone from the enemy ranks, and then attack in single combat. But they (the Mongols) took no notice at all of such conventions; they rushed forward all together in a mass, grappling with any individuals they could catch and killing them.[20]

— Hachiman Gudōkun

The History of Yuan gives a similar but shorter account:

Occupying the heights, his generals gave command by beating drums and the troops advanced or retreated according to the beat of the drums. When the enemy had moved into the pre-arranged positions, the invaders attacked from all sides. They also used firearms and [thus] slaughtered the enemy forces in countless numbers. Thus the Japanese were put to rout.[21]

— History of Yuan

The battle lasted for only a day and the fighting, though fierce, was uncoordinated and brief.[22] One low-ranking samurai, Takezaki Suenaga, received word from his commander Shōni Kagesuke that he was to wait until the Mongols advanced due to difficult terrain, but Takezaki attacked the Mongols anyway. On his way to the beach, he encountered Kikuchi Takefusa, who had already encountered a Yuan detachment, driven them away and killed two. Kikuchi told him the 'pirates' had already fled. Takezaki and his five companions charged the small Yuan detachment that Kikuchi had previously encountered, but their horses got stuck in the mud, and they were wounded by a barrage of arrows. Takezaki and three surviving retainers managed to retreat with the aid of Shiroishi Michiyasu, who charged the Yuan detachment and drove them away.[23][24] By nightfall the Yuan invasion force had forced the Japanese off the beach with a third of the defending forces dead, driven them several kilometres inland, and burnt Hakata.[25]

The Japanese were preparing to make a last stand at Mizuki (water castle), an earthwork moat fort dating back to 664.[26] However the Yuan attack never came. One of the three commanding Yuan generals, Liu Fuxiang (Yu-Puk Hyong), was shot in the face by the retreating samurai, Shōni Kagesuke, and seriously injured. Liu convened with the other generals Holdon and Hong Dagu back on his ship. Holdon wanted to keep advancing through the night before more Japanese reinforcements arrived but Hong was worried that their troops were too exhausted and needed rest. There was also fear of being ambushed in the night. Liu agreed with Hong and recalled the Yuan forces back to their ships.[27]

By morning, most of the Yuan ships had disappeared. According to a Japanese courtier in his diary entry for 6 November 1274, a sudden reverse wind from the east blew back the Yuan fleet. A few ships were beached and some 50 Yuan soldiers and sailors were captured and executed. According to the History of Yuan, "a great storm arose and many warships were dashed on the rocks and destroyed."[28] It is not certain whether the storm occurred at Hakata or if the fleet had already set sail for Korea and encountered it on their way back. Some accounts offer casualty reports that suggest 200 ships were lost. Of the 30,000 strong invasion force, 13,500 did not return.[29]

A story widely known in Japan is that back in Kamakura, Tokimune was overcome with fear when the invasion finally came and wanting to overcome his cowardice, he asked Mugaku Sogen, his Zen master, also known as Bukkō, for advice. Bukkō replied that he had to sit in meditation to find the source of his cowardice in himself. Tokimune went to Bukkō and said, "Finally there is the greatest happening of my life." Bukkō asked, "How do you plan to face it?" Tokimune screamed, "Katsu!" as if he wanted to scare all the enemies in front of him. Bukkō responded with satisfaction, "It is true that the son of a lion roars as a lion!"[30] Since then, Tokimune was instrumental in spreading Zen and Bushido in Japan among the samurai.

Orders for the second invasion came in the first lunar month of 1281. Two fleets were prepared, a force of 900 ships in Korea and 3,500 ships in Southern China with a combined force of 142,000 soldiers and sailors.[17] The Mongol general Arakhan was named supreme commander of the operation and was to travel with the Southern Route fleet, which was under the command of Fan Wenhu but was delayed by supply difficulties.[34]

The Eastern Route army set sail first from Korea on 22 May and attacked Tsushima on 9 June and Iki Island on 14 June. According to the History of Yuan, the Japanese commander Shōni Suketoki and Ryūzōji Suetoki led forces in the tens of thousands against the invasion force. The expeditionary forces discharged their firearms, and the Japanese were routed, with Suketoki killed in the process. More than 300 islanders were killed. The soldiers sought out the children and killed them as well. However, the History of Yuan merges events in June with the later battle in July, when Shōni Suketoki actually fell in battle.[35]

Japanese samurai boarding Yuan ships in 1281.

The defensive wall at Hakata

The Eastern Route army was supposed to wait for the Southern Route army at Iki, but their commanders, Hong Dagu and Kim Bang-gyeong, disobeyed orders and set out to invade Mainland Japan by themselves. They departed on 23 June, a full week ahead of the expected arrival of the Southern Route army on 2 July. The Eastern Route army split their forces in half and simultaneously attacked Hakata Bay and Nagato Province. Three hundred ships attacked Nagato on 25 June but were driven off and forced to return to Iki.[35]

Meanwhile, the rest of the Eastern Route army attacked Hakata Bay, which was heavily fortified with a defensive wall. Some Mongol ships came ashore but were unable to make it past the defensive wall and were driven off by volleys of arrows.[36]

Unable to land, the Mongol invasion force occupied the islands of Shika and Noko from which it had planned to launch raids against Hakata. Instead, the Japanese launched raids at night on board small ships. The Hachiman Gudōkun credit Kusano Jirō with boarding a Mongol ship, setting fire to it, and taking 21 heads.[37]

The next day, Kawano Michiari led a daytime raid with just two boats. His uncle Michitoki was immediately killed by an arrow, and Michiari was wounded both in the shoulder and the left arm. However, upon boarding the enemy ship, he slew a large Mongol warrior for which he was made a hero and richly rewarded. Takezaki Suenaga was also among those who raided the Yuan fleet.[38] Takezaki also participated in driving the Mongols from Shika island, although in that instance, he was wounded and forced them to withdraw to Iki on 30 June.[39]

The Japanese defence of Hakata Bay is known as the Battle of Kōan. On 16 July, fighting commenced between the Japanese and Mongols at Iki Island, resulting in Mongol withdrawal to Hirado Island.[40]

After the Southern Route fleet convened with the Northern Route fleet, the two fleets took some time rearranging themselves before they advanced on Taka island. After taking Taka island, the Yuan army advanced on Hakata. A two-week battle ensued throughout the countryside that entered a stalemate.[41]

On 12 August, the Japanese repeated their small raids on the invasion fleet that lasted throughout the night. The Mongols responded by fastening their ships together with chains and planks to provide defensive platforms. There are no accounts of the raids from the Japanese side in this incident, unlike at the defence of Hakata Bay. According to the History of Yuan, the Japanese ships were small and were all beaten off:[41][42]

Japanese war craft, being small in size, were no match [for these ships]. Those which came up to attack were all beaten off. The whole country therefore was trembling with fear. In the markets there was no rice for sale. The Japanese ruler went in person to visit the Hachiman Shrine to make supplication. He also had a royal rescript read at the shrine of the Sun Goddess, imploring that the country be saved in exchange for his own life.[43]

— History of Yuan

Wooden anchor of Mongol invasion

Stone anchor of Mongol invasion

On 15 August, a great typhoon, known in Japanese as kamikaze, struck the fleet at anchor from the west and devastated it. Sensing the oncoming typhoon, Korean and south Chinese mariners retreated and unsuccessfully docked in Imari Bay, where they were destroyed by the storm.[44] Thousands of soldiers were left drifting on pieces of wood or washed ashore. The Japanese defenders killed all those they found except for the Southern Chinese, who they felt had been coerced into joining the attack on Japan.

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.[43]

— Marco Polo

According to a Chinese survivor, after the typhoon, Commander Fan Wenhu picked the best remaining ships and sailed away, leaving more than 100,000 troops to die. After being stranded for three days on Taka island, the Japanese attacked and captured tens of thousands. They were moved to Hakata where the Japanese killed all the Mongols, Koreans, and Northern Chinese. The Southern Chinese were spared but made slaves. According to a Korean source, of the 26,989 Koreans who set out with the Eastern Route fleet, 7,592 did not return.[6] Chinese and Mongol sources indicate a casualty rate of 60 to 90 percent.[45]

Many modern historians believe the figures for the invasion force to be exaggerated, as was common in post-classical chronicles. Thomas Conlan, from Princeton university, writes that they were likely exaggerated by an order of magnitude, implying 14,000 soldiers and sailors, and expresses skepticism that a medieval-era kingdom could have managed an invasion on the scale of D-Day during World War II, across over ten times the distance, and questions if even 10,000 soldiers attacked Japan in 1281.[17]

Morris Rossabi writes that Conlan was correct in his assertion that the invasion force was much smaller than traditionally believed but argues that the expenditures lavished on the mission confirm that the fighting force was sizable and much larger than 10,000 soldiers and 4,000 sailors. He puts forward the alternative figure of 70,000 soldiers and sailors, half of what is stated in the Yuanshi and later Japanese claims.[46]

Turnbull thinks that more than 140,000 is an exaggeration but does not offer his own precise estimate for the size of the army. Rather, he states only that given the contributions of the Southern Song, the second invasion should have been around three times larger than the first. As he earlier listed the common figure of 23,000 for the first invasion uncritically, unlike the estimate of more than 140,000 for the second, which would imply an invasion force of around 70,000, on par with Rossabbi's estimate.[47]

The Zen Buddhism of Hōjō Tokimune and his Zen master Bukkō gained credibility beyond national boundaries, and the first mass followings of Zen teachings among samurai began to flourish.

The failed invasions also mark the first use of the word kamikaze ("Divine Wind"). The fact that the typhoon that helped Japan defeat the Mongol Navy in the first invasion occurred in late November, well after the normal Pacific typhoon season (May to October), perpetuated the Japanese belief that they would never be defeated or successfully invaded, which remained an important aspect of Japanese foreign policy until the very end of World War II. The failed invasions also demonstrated one of the Mongols' weaknesses – the inability to mount naval invasions successfully[54] (see also Mongol invasions of Vietnam and Java) After the death of Kublai, his successor, Temür Khan, unsuccessfully demanded the submission of Japan in 1295.

Stoneware bombs, known in Japanese as tetsuhō (iron bomb), or in Chinese as zhentianlei (literally, heaven-shaking thunder), excavated from Takashima shipwreck, October 2011.

The Mongol invasions are an early example of gunpowder warfare. One of the most notable technological innovations during the war was the use of explosive bombs.[7] The bombs are known in Chinese as "thunder crash bombs" and were fired from catapults, inflicting damage on enemy soldiers. An illustration of a bomb is depicted in the Japanese Mongol Invasion scrolls, but Thomas Conlan has shown that the illustration of the projectiles was added to the scrolls in the 18th century and should not be considered to be an eyewitness representation of their use.[55] However, archaeological discoveries since Conlan's statement have confirmed the existence of bombs in the Yuan invasion's arsenal. Multiple bomb shells were discovered in an underwater shipwreck off the shore of Japan by the Kyushu Okinawa Society for Underwater Archaeology. X-rays by Japanese scientists of the excavated shells show that they contained gunpowder and were also packed with scrap iron.[56][57]

The Yuan forces may have also used cannons during the invasion. The Taiheiki mentions a weapon shaped like a bell that made a noise like thunder-clap and shot out thousands of iron balls.[58][59]

Takezaki Suenaga and escaping Mongolians

The main weapon of the samurai is the bow and is able to shoot while riding on the horseback with the Japanese sword acting as a secondary weapon. But as a result of the war, intellectuals of the Mongol Empire regarded Japanese swords as a threat. For example, Wang Yun, who served Kublai, and Zheng Si-xiao, a surviving retainer of the Song Dynasty, mentioned in their book that "Japanese swords are long and extremely sharp." They argued that the combination of a violent samurai and a Japanese sword was a threat.[60][61] However, even so, the Mongol invasions of Japan facilitated a change in the designs of Japanese swords. The swordsmiths of the Sōshū school represented by Masamune studied tachi that were broken or bent in battle, developed new production methods, and created innovative tachi. They forged the blade using a combination of soft and hard steel to optimize the temperature and timing of the heating and cooling of the blade, resulting in a lighter but more robust blade. They also made the curve of the blade gentle, lengthened the tip linearly, widened the width from the cutting edge to the opposite side of the blade, and thinned the cross section to improve the penetration and cutting ability of the blade.[62][63]

• 
  A typical Ko-Hōki (old Hōki) school tachi. Dōjikiri, by Yasutsuna. 12th century, Heian period, National Treasure, Tokyo National Museum. This sword is one of the Five Swords Under Heaven. (天下五剣 Tenka Goken)
• 
  A Sōshū school katana. It was originally a tachi forged by Masamune in the 14th century, but later it was cut from the root and converted into a katana. As it was owned by Ishida Mitsunari, it was commonly called Ishida Masamune. Important Cultural Property, Tokyo National Museum.