In 369, as crown prince, Geungusu led the Baekje armies against invading troops of the northern Korean kingdom Goguryeo, capturing 5,000 prisoners.

His chief minister, Jin Godo (眞高道), was the father of his queen, Lady Ai (阿尒夫人).

However, on the basis of Korean accounts some believe that this took place decades later, in the reign of King Asin.

King Geunchogo dispatched the crown prince to repel them, and he reached Bangeolyang and was goiung to give battle.

Returning to Baekje at this time, he told the crown prince, "Their soldiers are many, but all of their numbers are meant to deceive you.

The crown prince followed his advice, and attacked and put them to a great rout, and he pursued them to the north, reaching all the way to the northwest of the fortress of Sugok.