Byeolmuban

Byeolmuban is the name of a special army unit in the time of Korea's Goryeo Dynasty (918–1392).

Founding of the army was initiated by Yun Kwan during the reign of king Sukjong of Goryeo.

The Goryeo infantry had a hard time resisting the strong Jurchen cavalry.

During the second year of king Yejong of Goryeo's reign the byeomuban, consisting of 17,000 soldiers, attacked Jurchen and killed approximately 5,000 Jurchen troops, detained another 5,000 POWs and 350 Jurchen tribal clans and took over their territory by building nine fortresses at Hamju region.

Fortresses were called Northeastern Nine Fortresses, and they are in Hamju (함주, 咸州), Yeongju (영주, 英州), Ungju (웅주, 雄州), Bokju (복주, 福州), Gilju (길주, 吉州), Gongheomjin, (공험진, 公咽鎭), Sungnyeong (숭녕, 崇寧), Tongtae (통태, 通泰), and Jinyang (진양, 眞陽).