This article examines men's use of physical punishment when interacting with their sons or grandsons in rural Vietnam. By drawing on two periods of anthropological fieldwork in a northern Vietnamese commune, the article analyses the ways in which violence is informed by, while also perpetually reinforcing, a masculine discourse. Vietnam has ratified the Convention on the Rights of the Child and in this spirit virtually all men in the local community disapprove of the use of physical punishment when bringing up boys. However, a father or grandfather occasionally beats his son or grandson when it is deemed necessary to instil discipline in a boy. The article elucidates the ways in which the contradictions between ideals of nonviolent behaviour and actual corporal punishment have fed the construction of certain codes regarding men's beating of boys. (Contains 20 notes.)