Also in Koan no Eki, what had destroyed the Southern Yangtze Army, which Japan could not know then, is said to have been a typhoon or tropical cyclone, but there is a theory that the Eastern Route Army staying offshore near Hakata perished due to a different reason.
弘安の役においても、当時の日本が知り得なかった江南軍壊滅の理由を台風や熱帯低気圧の影響としながらも、博多沖の東路軍は、それとは違った理由で壊滅したという説もある。