This is the detailed part of chapter 14|Late Kamakura Period History （鎌倉後期. Please read chapter 14 before reading this section.
The circle indicates the time we discuss in this section.
Genko (元寇): Mongolian Invasion
In Chapter 14, the Mongolian invasion was described simply. Here is the more detailed description. The Mongol Empire was a vast empire spread between present Mongol areas to Eastern Europe from 13 to 14 centuries. Grandson of Genghis Kahn, Kublai Kahn sent several official letters to Japan demanding Japan to become a dependency state of the Mongol Empire (元: Yuan) and demanded to send a tribute to them. They threatened Japan that they would invade if Japan did not accept their demand. Hojo Tokimune (北条時宗 ) who was in power in Kamakura Bakufu (government) at the time, refused and ignored the letters many times. That led to the two-time invasions by the Mongol Empire. It is often said that the strong typhoon hit Japan on each occasion and Mongols were chased away by these two big typhoons. This was correct but the real story was a lot more to it.
Bunei-no-eki (文永の役 ) 1274
The first Mongolian invasion was called Bunei-no-eki. In the early part of October 1274, 40,000 Mongol troops*¹ (Mongol, Han people, and Korean) departed from the Korean peninsula on 900*² large and small ships and headed to Japan. After they arrived on the Tsushima island (対馬 ), Mongol troop burnt villages and killed many people including the island people. Village people were captured and sent to the top officials of the Mongols as their slaves. It was a very sad scene. The Mongols moved to Iki island (壱岐の島), to Hizen shore (肥前 ), to Hirato island (平戸 ), to Taka-Shima (鷹島 ), then to Hakata bay (博多). At each place, the disastrous sad scene was the same as everywhere. At each battlefield, Japanese soldiers and villagers were killed in large numbers. The Kamakura Bukufu (government) sent a large number of samurai troops to the battlefield. The Japanese troops sometimes won and pushed the Mongolians back, but mostly the Japanese sides lost. Many wives and children of the Japanese side were captured. Eventually, even no soldiers dared to fight against the Mongols. Mongols arrows were short and not so powerful, but they put on the poison at the tip, and they shoot the arrows all together at one time like rain. Also, this is the first time the Japanese saw the firearms. The loud sound of the explosion made the horses and samurai frightened.
Japanese troops had to retreat and the situation was really bad for the Japanese. But one morning, a big surprise to the Japanese! All the ships disappeared from the shore, they were all gone on the morning of October 21st (today’s calendar, Nov 19th). All Mongols disappeared from the shore of Hakata. What happened was Mongols decided to quit the fight and went back to their country. The reason was; for Mongols, even though they were winning, they also lost many soldiers and lost one of the major key persons in the army. The Mongols realized that no matter how much Mongols won, the Japanese kept coming more and more from everywhere. Also, the Mongols realized that they could not expect reinforcements from their country across the ocean. Their stocks of weapons were getting low. It was the Mongols decision to go back. Here was a twist. Around the end of October (November by today’s calendar), the sea between Hakata (where Mongols were stationed) and Korea was a very dangerous sea because of the bad weather. Only a clear daytime of the south wind day is possible to sail over this sea. The name of the sea where the Mongol soldiers had to sail back is called Genkai Nada (玄界灘), very famous for the rough sea. For some reason, the Mongols decided to head back during the night. That was a mistake. They may have caught a moment of the south wind, but it did not last long. As a result, they encountered the usual severe rainstorm. Many ships hit against each other, against the cliff, ships capsized, people fell into the ocean, and several hundred broken ships were found on the Japan shore. The Mongol invasion ended here. This is called Bunei-no-eki (文永の役 ). Mongols lost a large number of people, ships, soldiers, food, weapons. Actually, it was Korea who lost a great deal, they were forced to supply all of the people, food, weapons, etc. by the Mongols. After this war, in Korea, only old men and children were left to work on the farm, on top of it, they had a drought and long rain.
Koan-no-eki (弘安の役) 1281
The second Mongolian invasion is called Koan-no-eki in 1281. After the first attempt to invade Japan, Kublai Khan kept sending messengers to Japan to demand to become a dependency state. The Kamakura Bakufu kept ignoring and killed messengers. Kublai Kahn decided to attack Japan again in 1281. The top advisers of Kublai Kahn tried to convince him not to do it because the ocean is too dangerous, the country is small, the place is too far, and nothing to gain even if the Mongols win. But Kublai Kahn still insisted to attack. This time they came in two groups. One was the East-route troop, the number was 40,000*¹ soldiers on 900 ships, and the other was South-route troop, the number was 100,000*¹ soldiers on 3,500 ships. This is the largest scale forces in history. They planned to depart from each one’s port and supposed to join on the Iki-no-shima island (壱岐の島) by June 15th, then work together. The East-route troop arrived there before the South-route troop came. Instead of waiting for the South-route troop to arrive, the East-route troop started to attack the Hakata Bay (博多) on their own. But since the previous invasion of the Binei-no-eki, Japan already prepared to fight and built a 20 kilometer long stone wall. This stone wall was 3 meters high and 2 meters thick. The East-route troop had to give up to land on Japan from Hakata and moved to Shiga-no-shima (志賀島). At this place, the fight between Mongols and Japan was even battle but at the end, East-route troop lost and retreated to the Iki-no-shima and decided to wait for the South-route troop to arrive. The South troop never came there, instead, they changed their plan. On top of that, while they were waiting for the South-route troop to arrive, they lost over 3,000 men over the epidemic. With difficulty like this, some suggested going back home but they concluded to wait for the South-rout troop to arrive as long as the food last. Meantime, the South-route troop changed their plan and decided to go to Hirato-Shima (平戸島) where it is closer to Dazaifu (太宰府). Dazaifu is the final and most important place they wanted to attack. Later, the East-route troop found out the South-route troop went to Hirato- Shima. Finally, two troops joined at Hirato-shima, and each group was stationed at a nearby island called Takashima (鷹島). The problem was that this island had very high tide and low tide, the ships were not easily maneuvered.
Meantime, 60,000 Japanese men were marching toward the place where the Mongols were stationed. Before Japanese soldiers arrived to fight against the Mongols, a big typhoon came on July 30th, and Mongols were caught in a big typhoon, ships hitting each other, people fell from the ships and drowned and the majority of ships sank. July 30th was about three months after the East- route troop left Mongol in early May. That means they were on the ocean and the shore of Japan for about three months or so. Around the north Kyushu area (北九州), usually, a typhoon comes average 3.2 times between July to September. Mongols were on the ocean and the shorelines of Japan for approximately three months; they were bound to be hit by a typhoon soon or later.
The Mongol Empire lost 2/3 of its naval forces at Koan-no-eki. Even after the Mongols failed two attempts to attack Japan, Kublai Khan still insisted to attack Japan the third time no matter how much his advisers reasoned him not to. In the end, the plan was delayed and terminated because of many rebellions, upheavals, and no lumber was left to build ships. Soon, Kublai died in 1294. The record book of Mongols and Korean indicated that Mongols officials gave a high evaluation toward Japanese swords. Some even say one of the reasons it was not easy to defeat Japan was because of the long sharp swords. The experience of the Mongolian invasion changed Ikubi Kissaki (猪首切先) sword to a new Soshu-Den (相州伝) style sword.
The stone wall scene. Photo from Wikipedia. Public Domain
*¹ Number of soldiers by https://kotobank.jp/word/元寇-60419 . Several different reference sources have a slightly different number of soldiers and ships, but they are similar numbers.