Battles & Wars › Medieval wars › Mongol conquests
Mongol invasions of Japan
1274 and 1281· War· Asia & Pacific
Well documentedSolid records, physical evidence or scientific consensus.
Kublai Khan sent two great seaborne invasions against Japan, in 1274 and 1281; both failed.
See it on the Battles & Wars map →What happened
After Japan's military government ignored demands to submit, a force of Mongol, Chinese and Korean troops, perhaps 25,000–40,000, landed at Hakata Bay in Kyushu in 1274 and withdrew after a day's fighting. In 1281 two much larger fleets came, from Korea and southern China. Samurai, behind a new stone wall along the bay, held them off for about two months, raiding the ships at night. Then a typhoon wrecked much of the fleet.
Why it matters
Japan stayed unconquered. The storms, remembered as kamikaze ('divine wind'), fed a belief in divine protection that wartime propaganda later revived.
How we know
Illustrated scrolls commissioned by the samurai Takezaki Suenaga; Yuan, Korean and Japanese records; remains of the stone wall; and wrecks and weapons found underwater off Takashima island.
Still debated
Fleet sizes (sources claim 4,400 ships and 140,000 men in 1281) are probably inflated, and whether a storm struck in 1274 at all is disputed.
Connections (5)
▸Mongol invasions of Japan used early exploding bombs, a product of Gunpowder and cannonWell documented
The connection
Yuan forces threw or catapulted ceramic bombs, called tetsuhau by the Japanese, packed with gunpowder and iron fragments. Their flash and blast frightened horses and stunned samurai who had never met such weapons. They show that by the 1270s Chinese gunpowder bombs were standard Mongol equipment, carried even across the sea.
When and how
Hakata Bay and Takashima, northern Kyushu, 1274 and 1281; Yuan Mongol, Chinese and Korean troops against Kamakura-era samurai.
How we know
A scroll commissioned by the samurai Takezaki Suenaga shows a bomb bursting near him, and underwater archaeology off Takashima has recovered actual bombs.
Debates and open questions
Parts of the scroll, including figures near the bomb, may have been added centuries later, and how much the bombs affected the fighting is unclear.
▸Genghis Khan was grandfather of Kublai, who launched Mongol invasions of JapanWell documented
The connection
Kublai Khan was a son of Tolui, Genghis Khan's youngest son. He inherited his grandfather's claim that Heaven had granted the Mongols rule over all peoples, so neighbors who refused to submit were treated as rebels. When Japan's shogunate ignored his demands, Kublai, now ruling China as the Yuan dynasty, invaded in 1274 and 1281.
When and how
Kublai's court at Dadu (Beijing); letters to Japan sent through Korea from 1266; invasions of Kyushu in 1274 and 1281.
How we know
A copy of Kublai's 1266 letter to the 'king of Japan' survives at Tōdai-ji temple in Nara, alongside Yuan and Korean annals.
Debates and open questions
Whether Kublai wanted conquest or mainly submission and trade, and whether he aimed to cut Japan's ties with the rival Song, is debated.
▸Mongol conquests failed at sea in Mongol invasions of JapanWell documented
The connection
Subduing Korea and southern China gave the Mongols shipyards, sailors and troops to strike across the sea. Korea's Goryeo kingdom was forced to build most of the 1274 fleet, and surrendered Song Chinese soldiers filled much of the 1281 one. But steppe tactics did not travel well by sea; later naval expeditions to Vietnam (1288) and Java (1293) also failed.
When and how
Korea's south coast and Kyushu, Japan, 1274 and 1281; the Yuan court under Kublai, with Korean shipbuilders and former Song troops.
How we know
The official Yuan history and Korea's Goryeosa record the fleets' construction and losses; wrecks off Takashima show hastily built ships, some unfit for open sea.
Debates and open questions
The claimed size of the 1281 fleet is doubted, and whether storms or Japanese defenses did more to defeat it is still debated.
▸Japanese sword (tachi and katana) faced the Mongol invaders in the Mongol invasions of JapanMostly agreed
The connection
In 1274 and 1281 samurai met Mongol, Korean (Goryeo) and Chinese troops on Kyushu's shores. Their main weapons were the bow and the long tachi. The invaders fought in massed formations with exploding bombs, unlike samurai single combat. In 1281, Japanese night raids on the anchored fleets used swords at close quarters, before a typhoon wrecked much of the fleet.
When and how
Hakata Bay and Takashima island, Kyushu, 1274 and 1281; warriors of the Kamakura shogunate against Yuan and Goryeo forces.
How sure are we?
The Mongol Invasion Scrolls, made for the samurai Takezaki Suenaga, show tachi and bows in use; underwater finds at Takashima include weapons and bombs.
Debates and open questions
Later lore says the invasions pushed swordsmiths to make thicker, tougher blades; evidence for that change is thin and debated.
▸Masamune, Japan's most famous swordsmith is said to have improved blades after the Mongol invasions of JapanDebated
The connection
During the Mongol invasions of 1274 and 1281, Japanese warriors are said to have found their long, delicate tachi chipping against the invaders' hardened leather armor. The story goes that Masamune and his teachers' generation developed tougher, thicker blades in response.
When and how
Northern Kyushu, around Hakata Bay, 1274 and 1281; Sagami smiths, about 1290–1330.
How sure are we?
The timing fits and blade styles did change around 1300, but no contemporary record ties the change to the Mongols.
Debates and open questions
Many scholars treat the Mongol link as an attractive later story; changing fighting styles in Japan's own wars may explain the new blades.