For the ships of that time, it was dangerous to voyage towards the north from Hakata to Goryeo except on a sunny day with south wind, and sometimes it took a month in this season waiting for a good weather.
当時の艦船では、博多‐高麗間の北上は南風の晴れた昼でなければ危険であり、この季節では天気待ちで1ヶ月掛かる事もあった。