In this paper the author examines the divination techniques of a Vietnamese highland minority, the Bru (Van Kieu). One of the characteristics of Bru religion and shamanism is that during religious rituals constant contact is maintained with the supernatural world via divinations. After discussing the different means of it, the author argues that they are to be understood as reflections of a sceptical and rational world view in which humans need continuous confirmation from the representatives of the supernatural world.