Cika wannan jumla:
A lokacin mamayewar Mongol na Kievan Rus', sun yi amfani da kogunan da suka daskare a matsayin manyan hanyoyi, kuma hunturu, lokacin shekara-shekara wanda ba shi da iyaka ga duk wani babban aiki saboda tsananin sanyi, ya zama lokacin da Mongols suka fi so ya kai hari.