黒旗軍
In December 1883 the Black Flag Army suffered a major defeat at the hands of Admiral Amédée Courbet in the Sơn Tây Campaign. Despite fighting with fanatical courage in the engagements at Phu Sa on 14 December and Son Tay on 16 December, the Black Flags were unable to prevent the French from storming Sơn Tây. Even with large Chinese and Vietnamese regular contingents at Son Tay, the Black Flag Army bore the brunt of the fighting, and took very heavy casualties. In the opinion of the British observer William Mesny, a senior officer in the Chinese army, the fighting at Sơn Tây broke the power of the Black Flag Army, though the stubborn defence put up by the Black Flags in the Battle of Hòa Mộc fifteen months later does not bear out this assessment.