Goryeo–Mongol Tensions

Timeline

1. 1218North of the Yalu River · Pyeongannam-doMongol general Qaraji led his troops in pursuit of the fleeing Khitan leader and his followers, crossing the Yalu River into Goryeo territory. The Mongols demanded passage on the pretext of suppressing rebels; Goryeo border commanders stood on alert and clashes broke out, sharply straining relations between the two states.
2. 1218Around the western capital Pyongyang · Pyeongannam-doKing Gojong of Goryeo ordered generals to lead troops in resistance, but Mongol cavalry mobility was strong and fighting occurred several times along the border. Goryeo forces could not effectively block them, and northwestern towns were plundered. The court was divided over peace or war, and flaws in the border defense system were exposed.
3. 1218Ganghwa Island · Incheon Metropolitan CityAs the fighting intensified, Goryeo began moving supplies and royal clan members to Ganghwa Island, building fortifications for a prolonged standoff. Though this temporarily secured the royal family's safety, it also marked Goryeo's recognition of the Mongol threat rising from a border skirmish to an existential crisis.