Cần Vương movement
Giáp's father was both a minor official and a committed Vietnamese nationalist, having played a part in the Cần Vương movement in the 1880s. He was arrested for subversive activities by the French colonial authorities in 1919 and died in prison a few weeks later. Giáp had two sisters and one brother, and soon after his father's incarceration, one of his sisters was also arrested. Although she was not held for long, the privations of prison life made her ill and she too died a few weeks after being released.