The Mongols are famous for their broad, rapid conquests and the gargantuan empire that they build as a result. They conquered numerous great states, such as the Chinese Song Dynasty and the Persian Khwarazmian Empire, thereby taking their great resources for themselves. But on the fringe of the Mongol's greatest centre of power, Kublai Khan's Yuan Dynasty, sat the island of Japan whose government refused to pay tribute to Kublai and did away with his messengers. In response the Mongols sought to conquer Japan as punishment but failed not just once but twice. So what caused this? Why couldn't the Mongols conquer Japan despite all of its advantages.