What is "byeolgigun"

The Byeolgigun ( Korean: 별기군, "Special Skills Force" or "Special Army") was the first modernised military force of Korea. First conceived in 1876, it was formed in 1881 and trained by Japanese officers led by Horimoto Reijo, military attaché at the Japanese legation. It received better treatment than the old Korean Army, whose soldiers' salaries were in arrears on account of the costs of the Byeolgigun. This led in 1882 to the Imo mutiny, in which soldiers rioted and Horimoto Reijo was killed.