Skip to main content

Bad Weather Wasn't the Only Cause of Mongol Defeat in Japan

What lead to the Mongol defeat in Japan?

What lead to the Mongol defeat in Japan?

The Yuan Dynasty

With a lot of conquered territories, Kublai Khan’s Mongol forces demanded reverences and respect. The fifth Khagan leader ruled a vast empire, stretching from Eastern Europe and extending as far as the Levant. During his term, China came under his rule, and the Yuan Dynasty was established. He commanded an army of swift mounted archers, renowned for their tactics and feigned retreats.

The Mongol hordes were both impressive and frightening, all the same, being one of the most powerful military forces during that age. And during the 13th century, the Khan sets his sight on a new target. Across the sea, Korea became a vassal state of the Yuan Dynasty, and Japan was next.

But we knew what happened.

Even the mighty army of the Kublai Khan was no match to mother nature. The Yuan Dynasty’s attempts to conquer Japan always brings to mind barely organized Samurai forces struggling to fight a well-guided Mongol army. They were on the brink of defeat, if not for a series of storms that wrecked the Mongol fleet. The gods seemed to favor the Samurai at that time.

Yet, the Yuan Dynasty’s conquering forces faced more than mother nature in their stay in Japan. The Samurai forces already did a lot of damages even before the divine winds arrived.

Forces Compared

A depiction of a Mongol horse archer.

A depiction of a Mongol horse archer.

The Mongol conquest of Japan pitted some of the most well-known military powers in history. Going full offense was the Yuan Dynasty Mongol army. The famed mounted warriors of Kublai Khan were his inheritance from his grandfather Genghis Khan. It terrorized Eastern Europe and conquered almost all of Asia. Horse archery and unit formations were its core, supported by well-organized logistics. The command structure was flexible, enabling the army to execute quick maneuvers. Weapons included swords and various bladed implements, and their conquest of China gave them access to gunpowder. But their composite bows were their prime military assets.

Kublai Khan was about to bring his well-disciplined and organized army into Japan. But Japan has its own fangs to bear, in the form of the Samurai warriors.

Samurai reenactors, in Kamakura period armors.

Samurai reenactors, in Kamakura period armors.

The Samurai never earn their reputation as fierce warriors for nothing. The established shogunates, being constantly at war with each other produced some of the battle-hardened fighters there were in their period. They were brave and violent, clad in lamellar armor (at that time), and armed with well-made bladed weapons. Like the Mongols, they were trained in horse archery. The dilemma here was that the Samurai forces were restricted to their own style of fighting, consisting of traditionalized battles and ritualized duels. Though fierce and brutal, they lacked the precise and swift military organization of the Mongols.

Or at least, that was what’s initially thought.

With their victories in Eastern Europe and several parts of Asia, an easy win over the shogunate forces seemed assured. But that was not the case in both invasion attempts. In fact, their battles in Japan were bloodier than expected.

Kublai Khan Sent a Different Army

Painting, showing Yuan army formation during the Invasion of Japan.

Painting, showing Yuan army formation during the Invasion of Japan.

One thing to consider here is that the forces the Khan sent were far different than the usual Mongol forces. Only a small portion of which were Mongolian cavalries. According to sources, there were 23000 men deployed to fight in Japan. 15000 of which composed of Mongols, Jurchens, and Chinese. The rest were Korean soldiers. With the percentage taken to consideration, most were not Mongolians at all. The Japanese account stated that the invading forces compose of Koreans and Chinese foot soldiers commanded by Mongol horsemen. It might be possible that the Samurai forces fielded more horse archers of their own, unlike the Yuan forces.

With that said, the Khan's Yuan army cannot be considered as a Mongolian Army. With a lot of foreign fighters in their ranks, communication was more difficult, and discipline was lower. And with the knowledge that they are captive soldiers fighting under a conquering leader, morale among the foreign soldiers was also low. This came in contrast with the dedicated Samurai forces who were more than willing to fight to the death.

The Samurai in Combat

Samurai forces fighting on horseback.

Samurai forces fighting on horseback.

The Samurais were always associated with the sword, but they have also mounted archers with the swords serving as sidearms. The way they fought were often romanticized as honorable singles combat, much like the western Knights. But the Samurai warriors could be treacherous or backstabbing if the need arises, and the battles they fought never resembled duels. The Samurai were simply as practical as any soldiers of their period, and when they fight, they were not as sloppy as what was assumed.

They were not as tactically organized as the Mongol invaders, but there was certain level of coordination when their mounted cavalries fought. They rode supported by infantries, and guided by flag signals. They were capable of quick skirmishes, surprise attacks and raids.

And It Became Bloody for the Invaders

Kikuchi Takefusa, one of the Samurais that helped defeat the invading Yuan army.

Kikuchi Takefusa, one of the Samurais that helped defeat the invading Yuan army.

With a different Mongol army coming into consideration, the fight to take Japan never went as planned. In fact, the notion that the Samurai was struggling for a victory and won through sheer luck was false. During both invasion attempts, the shogunate forces scored several victories, particularly in the second invasion attempt even after the Yuan army prevailed in earlier battles. And during those victorious battles, the Yuan army suffered heavy casualties, which forced them to withdraw.

Going back to the first invasion attempt, the Samurai forces was never caught off-guard. When words came out of a possible invasion by the Yuan forces, the shogunate began to prepare defenses and manpower. The result was a Samurai army larger than the invading force. The use of surprise attacks by the Kikuchi Takefusa ended with the defeat of the Yuan force in Akasaka. 3500 Mongolian soldiers also perished in the Battle of Torikai-Gata after being assaulted by Takezaki Suenaga, with reinforcements coming from Shiraishi Michiyasu.

The failure to field more cavalry on the Mongolian side also never gave the Yuan army additional tactical advantage. In fact, the Samurai forces had more cavalries than the invading army. The Yuan forces did mass their infantries in formations, with portable shield walls and polearms. Many samurais were unhorsed but employing more cavalries enabled Shiroishi Michiyasu to break enemy formations and force a retreat on the enemy side. There was also a case where Liu Fuxiang, a Yuan commander got shot to the face with the arrow of Shoni Kagesuke.

The exhausted Yuan army withdraw into their ships, where they were vulnerable to night raids by Samurais.

And the typhoon finished the rest.

Fortifications and Close Combat

Genkō Bōrui defensive walls constructed along Hakata Bay.

Genkō Bōrui defensive walls constructed along Hakata Bay.

During the Mongol campaign in Eastern Europe, fortifications were proven defenses against the marauding hordes. The shogunate did the same by constructing walls along Hakata Bay. This proved to be effective, as it denied the invading Yuan forces a proper landing site and opening them to the raids and skirmishes by Samurai forces in their boats.

And now that we spoke of skirmishes, another factor that gave the Yuan forces a hard time was their inability to fight in closed quarters.

As the Mongol fleet stayed stranded in the Bay, the Samurais staged night raids in their ships, forcing the Mongol warriors to fight up close. In the confines of their ships, the Yuan soldiers were unable to bring their bows and arrows quickly enough to stop the charging Samurais. With the superior skills of the Samurais to fight in such a manner, a lot of Yuan soldiers were slaughtered. Fighting up-closed also gave the Samurais an advantage during field combat, with reports of several enemy heads being taken.

Substandard Yuan Ships

Samurais raiding a Mongol ship.

Samurais raiding a Mongol ship.

But perhaps the biggest undoing of Kublai Khan was sending poor quality ships, particularly in the second invasion attempt. During the planning of the second invasion, the Khan rushed the rebuilding of the fleet, and he ended up with substandard vessels, some not even worthy to stand rough weather. And when the second invasion commenced, the invading Yuan forces were forced into a stalemate. They failed to make significant gains in the land, thanks to fierce resistance by the Samurai defenders. Reinforcement for the Yuan forces then arrives, in the form of two fleets of 4000 ships as what was estimated by the Japanese forces. But the tempest struck at the Tsushima Strait, the fabled Kamikaze believed to be a storm conjured by the gods. The poor construction of the ships meant that they cannot survive the incoming weather disturbance, and the fleet was destroyed.

The survival of the fleet could have made a difference had it escaped intact, but even if it did, it still faced a wall of samurai defenses inland. Seeing the situation in Hakata, where the Yuan army was stuck in a stalemate, the storm was more as coupe de grace to a dying enemy, as historian T. Conlan described it.

And going back to the first invasion, accounts indicated that the first of the divinely conjured winds struck as the invaders were making a retreat. Due to the defeat in Torikai-Gata, and the constant harassment made by the Samurai forces, the Korean commander Hong Dagu had enough and decided to withdraw to Korea. On their way, they hit a storm with most of the ships being reduced to wreckage.


The Mongol defeat in their invasion attempts was never due to dumb luck or bad weather. The fabled wind was devastating on its own but hardly a tactical advantage. With an army of mixed nationalities, limited Mongol cavalry, and facing fierce defenders that drove them into a bloody stalemate, the Mongol empire never fared better in their attempts in Japan.


  1. Turnbull, Stephen (19 February 2013). The Mongol Invasions of Japan 1274 and 1281. Osprey Publishing
  2. Delgado, James (February 2003). "Relics of the Kamikaze". Archaeology.
  3. Delgado, James P. (2010). Khubilai Khan's Lost Fleet: In Search of a Legendary Armada.
  4. Mongol Invasion of Japan (元寇): Part 1 - Some quick myths about the invasion