The Battle of Bun'ei, also known as the First Battle of Hakata Bay, is the first attempt by the Yuan Dynasty, founded by the Mongols, to invade Japan.
After conquering the Japanese settlements on Tsushima and Iki islands, Kublai Khan's fleet moves on to Japan proper and lands at Hakata Bay, a short distance from Kyūshū's administrative capital of Dazaifu.
Despite the superior weapons and tactics of the Mongols, who have just established the Yuan Dynasty in China, the Yuan forces that disembark at Hakata Bay are grossly outnumbered by the samurai force; the Japanese had been preparing, mobilizing warriors and reinforcing defenses since they heard of the defeats at Tsushima and Iki.The Yuan troops withdraw and take refuge on their ships after only one day of fighting.
A typhoon that night, said to be divinely conjured wind, threatens their ships, persuading them to return to Korea.
Many of the returning ships sink that night due to the storm.