Sakju

Sakchu lies in the mountains near the Yalu River on Korea's northwestern frontier. It was one of the strongpoints linked by Koryŏ's great frontier wall, completed in 1044 after wars with the Khitan. Under Joseon, the district's boundaries were reorganised in 1394, and Sakchu was raised to the rank of a protectorate in 1413. Forts, passes and beacon stations reflected its continuing role in border defence.