By the middle of the 13th century, the Mongol Empire was the largest state on the planet. To jump ahead a little: the only empire ever bigger than the Mongol one was the British.
The Mongols subdued vast territories — from Poland in the west to Korea in the east. In 1258, for instance, the Mongols destroyed Baghdad along with its thousand-year-old system of canals, which no one was ever able to restore. In the east, the Mongols seized everything that today is called China, and even launched their own Yuan dynasty with its capital in the future Beijing.
In 1265, Khan Kublai (grandson of Genghis Khan) was informed that off to the east there were still some unconquered barbarians. Trouble was, they lived on islands, so you couldn’t get to them on horseback. Here it’s worth remembering that the Mongols never much fought on water, on the grounds of “why would we?”
In 1266, Kublai sent a letter to Japan. “We consider all countries to be members of one family. No one wishes to take up arms.” In short: acknowledge yourselves our vassals, with everything that follows. Japan back then was, let’s put it plainly, not the most open of states. They hadn’t sent envoys to China since the year 894. So Kublai didn’t even get a reply to his first letter.
From 1269 to 1272, Kublai sent another four embassies. To no avail. The subscriber was unavailable. Completely. The last two expeditions didn’t even get permission to land, let alone talk. In short, the regent of the day, Hōjō Tokimune, added Kublai to his blocklist and set about building coastal fortifications in strategically important spots. Just in case. You never know.
Kublai started building ships. Obviously the Mongols understood ships about as well as I understand military helicopters (that is, not at all). But the Koreans knew what was what. In 1274, some 700-plus vessels with 20-plus thousand soldiers sailed to the shores of Japan.
At first everything went well. Never before had an army like this come to Japan from abroad. On top of that, the aggressor had new technology. Bombs and all that. So the samurai kept losing. Japan would probably have become a vassal state and joined the happy (not really) family of the Mongol Empire. But on November 19 a strong wind rose, and the storm sank half of the Korean-Chinese-Mongol fleet. The samurai finished off the rest.
In 1275, Kublai sent another five envoys. For the ruler of an enormous empire, it was strange that some islanders were systematically ignoring him. Only the heads of his negotiators came back to the future Beijing. A second batch of envoys, in 1279, was likewise beheaded.
In 1281, more than 4,000 ships set out toward Japan. Until World War II, this was the largest armada in human history.
In medieval Japan, the emperor was usually either a child or a monk. As a rule nobody consulted him or paid him much mind. The regents ruled “on his behalf and by his authority.” History records three occasions on which a regent went to the emperor for advice. Well — this was one of those occasions.
When the fleet approached the coast, it became clear that the Japanese hadn’t wasted all those years: they’d built serious fortifications. You couldn’t just waltz ashore. And after that it went like last time. At some point the wind rose, and the flimsy Chinese flat-bottomed boats couldn’t survive it.
This wind the Japanese named “Shinpu,” or “Kamikaze” — the divine wind.
After that, Kublai gave up on Japan. And the Japanese got one more confirmation that they were a people chosen by the gods, protected by those same gods, and therefore invincible. That conviction held all the way until August 1945.