Eupseong is a technology in Age of Empires II: Definitive Edition that is unique to the Koreans and can be researched at the Castle. Once researched, it increases the range of Watch Towers, Guard Towers and Keeps by +2. It replaces Panokseon.
Eupseong synergizes well with the free tower upgrades Koreans get automatically upon advancement to the next age. With the increase in range, Korean towers can attack units from further away and take the enemy down before they get too close. Also, if used offensively, Koreans should establish defensive buildings around the enemy base as early as possible to disrupt their economy.
Eupseong can be translated as a 'city fortress'. Korean fortresses have been constructed since the Three Kingdoms of Korea period and developed a unique and distinct fortress tradition. Almost 2,400 mountain fortress sites have been found in Korea.
- Before the introduction of Eupseong, Korean towers received +1/+2 range in the Castle/Imperial Age. Eupseong is meant to replace this bonus. Despite having resource cost (as opposed to the former bonus being free), it offers +2 range at an earlier stage (i.e. in the Castle Age).
- With update 42848, Eupseong introduced to replace Panokseon. Koreans lose their "free" bonus to tower range.