元寇
During the middle Kamakura period, Japan suffered from the invasions of the Mongol Empire (Yuan dynasty), which was then dominant on the continent, and its partner kingdom, the Goryeo of Korea. The History of Yuan states that the Mongol invasions of Japan began with King Chungnyeol of Goryeo "persistently recommending an expedition to the east to Yuan's emperor in order to force Japan to become its vassal state." In order to invade Japan, the Mongols ordered the Korean king to manufacture 1,000 warships. The two Mongol – Korean fleets were destroyed by storms, giving rise to the myth of the Kamikaze, the divine winds that protected Japan. At the time of Mongol invasions of Japan, Japanese people were scared by the attacks of the Mongol and Goryeo army, saying, 'moko kokuri no oni ga kuru (the devils of the Mongol and Goryeo will come)', which phrase later came to represent something scary; thus a tradition spread to the whole country to scare children into obedience by saying 'mukuri kokuri, oni ga kuru'.