The Joss charm container is similar in form to the much larger n’koko ngoombu percussion instrument, which is part of the paraphernalia of a diviner. The head surmounting the handle appears to objectify the role of elders in mediating misfortune, sickness, and death. There is an implied reference to the powers of extravision attributed to those in authority, which enables them to see past the appearances of ordinary life into the nefarious world of envy, witchcraft and sorcery. The diviner’s vision is an internal vision, which is most clearly revealed only when he or she “dreams” on a given matter. The charm ingredients originally inserted in this object were determined by the needs of the maker and user. Some elements appealed to the goodwill of elders and ancestors, others asserted how and in what direction the power charge was to act, and still others had cosmological referents uniting dyadic opposites, mediatory categories, and two of the triadic colors. This bundle of charm ingredients was then triggered by appropriate verbal formulae.
Source: Ross, Doran H. ed. (1994): “Visions of Africa”, Los Angeles, UCLA Fowler Museum of Cultural History. page 120