Japanese samurai boarding Mongol ships.

Japan

The Mongols were not content with simply ruling over the Eurasian continent. The also sought to conquer abroad, namely to conquer Japan. After the lengthy invasions of Korea ended in a treaty in 1259 with Korea becoming a Mongol vassal, and after Kublai Khan became Great Khan of the Empire in 1260, the Mongols set their sights on Japan.

In 1266, Kublai Khan sent emissaries to Japan with a letter demanding that Japan submit itself to Mongol rule and become a subordinate vassal state. Though the emissaries threatened warfare on Japan, the returned without a reply. When the second set of messengers sent two years later also returned empty-handed, Kublai Khan decided to go to war, but realized that his army was unequipped to do so. Instead, he sent numerous Korean envoys to persuade Japan to surrender to Mongol rule.

By 1274, when Japan continuously refused to give in to Mongol demands, Kublai Khan sent a fleet of 23,000 Mongol, Chinese, and Korean soldiers in nearly 800 sea vessels. Setting out from Korea, the Mongol fleet made significant gains on the Japanese, who had never before seen an army of that size. Armed with superior weapons, including poisoned arrows and gunpowder, the Mongols won the initial battles.

Mongol Japanese Korean fighting

The samurai fighting against Mongol and Korean arrows and canons.

However, severe storms left Mongol troops marooned on Japanese soil, as 200 Mongol ships were destroyed. The Japanese were well-equipped to handle such weather with more agile sea vessels. Boarding the remaining Mongol ships, the Japanese samurai forced the crippled Mongol army into submission.

Japan knew that the Mongols wouldn’t give up that easily, so starting in 1275 – barely a year after the first invasion – they made defense preparations. Sure enough, in the spring of 1281, the Mongols again sent forces to conquer Japan, this time with a coordinated attack of 900 ships manned by 40,000 Mongol, Chinese, and Korean troops to be supported by 100,000 Chinese on 3,500 ships. But again, natural causes would prove to be in Japan’s favor. The Chinese navy was delayed due to difficulties manning and supplying the massive fleet, while the Korean troops retreated after suffering losses at Tsushima. The combined forces of the Korean and Chinese fleets engaged the Japanese in the Battle of Koan. But the now-fortified Japanese coast held, though they were heavily outnumbered by the Mongols.

Mongol fleet being destroyed in the typhoon.

A nineteenth century drawing of the Mongol fleet destroyed in the typhoon.

The decisive blow against the Mongols was a massive 2-day long kamikaze typhoon that completely destroyed Mongol ships. This was because the Mongols built the ships so quickly that they created simply Chinese, flat-bottomed river boats. These boats did not have the curved keel that prevents capsizing, rendering them unfit to handle high waves, let alone a typhoon.

Japan marker

A Japanese marker of the location of a fortress used to defend against the Mongols.

Though the Mongols never succeeded in conquering Japan, the attempts nevertheless defined history. The defeat established Mongol borders along the Eurasian mainland and solidified Japanese independence. It also marked a turning point in military history. This was the first time gunpowder was used in battle, and the first time the samurai fought an outside enemy instead of the constant Japanese infighting. It was also the first time the term kamikaze, meaning “Divine Wind,” was used, symbolizing Japan’s belief in its inability to be defeated Most importantly, the invasions proved that though the Mongols were a force to be reckoned with on the battlefield, they were inexperienced and ill-equipped to fight naval battles.