Mongol invasions of Japan

The Mongol invasions of Japan were major military efforts led by Kublai Khan of the Yuan dynasty in the years 1274 and 1281. After the Korean kingdom of Goryeo became a vassal state, Kublai Khan turned his attention to the Japanese archipelago. His goal was to add Japan to his vast empire, making these invasions important moments in the history of Japan.

Although the Mongols were powerful, these invasions ultimately failed. This was largely because of strong resistance from the Japanese and natural disasters. The most famous of these were huge typhoons that destroyed the Mongol fleets. These storms were later called kamikaze (神風), meaning "divine wind," because many believed they were sent by the gods to protect Japan.

These events are also significant because they were among the earliest examples of gunpowder warfare outside of China. During the invasions, soldiers used new kinds of weapons, including explosive bombs that could be thrown by hand. The story of the Mongol invasions has been told in many books, movies, and even influenced the meaning of the word kamikaze, which centuries later described Japanese pilots who crashed their planes into enemy ships during World War II.

Background

See also: Mongol invasions and conquests and Military of the Mongol Empire

After the Mongol invasions of Korea, the Korean kingdom of Goryeo agreed to follow Mongol rules and became a smaller nation under Mongol control. Kublai Khan became the leader of the Mongol Empire and set up his capital in what is now Beijing.

At that time, Japan was ruled by leaders called the Shikken from the Hōjō clan. They had taken power from the Kamakura shogunate. The Mongols also tried to control people living on the island of Sakhalin, including the Ainu and Nivkh peoples, but it is unclear if this was part of their plan to attack Japan.

Contact

Between 1266 and 1273, Mongol and Korean diplomats visited Japan six times to ask the Japanese to join the Mongol Empire. The Japanese ignored these requests.

In 1265, a Korean citizen suggested to Kublai Khan that Japan should become a vassal of the Mongols. Kublai sent envoys to Japan, but they faced many obstacles. The Japanese treated them poorly, forcing them to stay in basic lodgings and refusing to meet with them properly. These disrespectful treatments upset Kublai, who sent more envoys, but each time the Japanese either ignored them or treated them harshly. By 1273, the Mongols were angry and frustrated with Japan's refusal to respond.

First invasion preparations

In April 1274, the Yuan dynasty prepared for an invasion of Japan. General Kim Panggyong led a force to build ships in Korea, creating three types of vessels for the fleet. The invasion was planned to attack Tsushima Island, Iki Island, and Hakata Bay. The Japanese defenders, led by local lords known as gokenin, aimed to resist the invaders at every step.

The Yuan forces included 15,000 soldiers from Mongol, Han Chinese, and Jurchen groups, along with thousands of Korean troops and sailors. During this time, a Japanese leader named Tokimune sought advice from his Zen_master, Mugaku Sogen, on how to face the invasion. After meditation, Tokimune found courage and later helped spread the practice of Zen and Bushido among samurai in Japan.

First invasion (1274)

Main article: Battle of Bun'ei

In 1274, Kublai Khan of the Yuan dynasty sent a large fleet to Japan, aiming to conquer the islands. The first landing happened on Tsushima Island, where a small group of Japanese defenders fought bravely but were overwhelmed by the much larger invading force. The invaders then moved to Iki Island and finally to Hakata Bay on the island of Kyushu.

The battle at Hakata Bay, known as the Battle of Bun'ei, saw both sides fighting fiercely. The Japanese were surprised by the Mongols' tactics and weapons, which included explosive bombs that confused their soldiers. Despite their best efforts, the Japanese were forced back, but the Mongol forces decided to withdraw to their ships due to exhaustion and fear of nighttime ambushes. The next morning, most of the Mongol ships had vanished, likely destroyed by a sudden and powerful storm. This natural disaster prevented the invaders from continuing their attack, marking the end of the first invasion attempt.

Second invasion preparations

After the first invasion in 1274, the Japanese leaders worked hard to prepare for another possible attack. They organized their soldiers better and built strong walls and other defenses at places where the invaders might land, such as Hakata Bay. They also placed many sharp stakes in the water to make it hard for enemy ships to approach.

In 1275 and again in 1279, Kublai Khan sent messengers to Japan, but the Japanese leaders executed them. Later, Kublai planned a bigger invasion using forces from many parts of his empire, including over 1,500 ships and many soldiers. Though the exact numbers are uncertain, this second invasion was intended to be much larger than the first.

Second invasion (1281)

Main article: Battle of Kōan

In 1281, Kublai Khan launched a second major invasion of Japan. Two large fleets were prepared—one from Korea and another from southern China—with soldiers and sailors ready to attack. The plan was for both fleets to work together, but the fleet from Korea moved earlier than planned.

The Korean fleet attacked islands close to Japan, facing strong resistance from Japanese defenders. The battle was tough, and many soldiers from both sides were hurt or lost in the fighting. Later, the main fleet from China joined the battle near a well-defended area in Japan. For weeks, the two sides fought without a clear winner.

Finally, a powerful typhoon struck the invading fleet. The strong winds and waves destroyed many ships and caused great loss of life among the invaders. This natural disaster, later called kamikaze or “divine wind” in Japanese, helped the defenders of Japan and ended the invasion. The failed attempt showed the strength of nature and the challenges of large military operations across great distances.

Aftermath

The Mongol Empire was weakened after these invasions, losing much of its naval strength. Korea, which helped build ships for the attack, also suffered because many trees were cut down. In Japan, the leaders who fought back were not rewarded with new land, which weakened their power. Over time, more Japanese began attacking the coasts of China and Korea.

The invasions had a big effect on culture too. Zen Buddhism, taught by leaders like Hōjō Tokimune, became more popular. The term kamikaze ("divine wind") was first used to describe the typhoons that destroyed the Mongol ships. These storms made many Japanese believe their nation was protected and hard to invade, a belief that lasted for many years. The invasions also showed that the Mongols struggled with naval attacks.

See also: Mongol invasions of Vietnam and Mongol invasion of Java

Military significance

The Mongol invasions of Japan were important because they showed early use of gunpowder weapons outside of China. The Mongol forces used explosive bombs, which were fired from catapults. These bombs contained gunpowder and scrap iron, and pieces of them have been found in underwater shipwrecks near Japan.

Japanese samurai fighters used longbows called yumi and weapons named naginata. They also used swords, which the Mongols saw as very sharp and dangerous. After these battles, Japanese sword makers improved their designs, creating stronger and better blades.