This is the 7502nd most frequent Korean word.
침공에
"침공에" means "to invasion" or "in the act of invasion."
In this sentence, '침공에' is used as a locative marker to indicate focus on the act of invasion when preparing.
적의 침공에 대비하다.
To prepare for an enemy's invasion.
Here, '침공에' marks the context of achieving success in the invasion, emphasizing the culmination of efforts.
침공에 성공한 군대는 성에 진입했다.
The army that succeeded in invasion entered the castle.
'침공에' is utilized to specify the context of focus where strategy failed, the invasion.