Taoist funerary ritual treats death as an administrative problem. The soul must be located, its accumulated debts to the underworld bureaucracy computed and settled, and its passage secured — which is done with written documents, spirit money and paper effigies of houses, cars, servants and, in contemporary practice, phones and appliances, all burned so they transfer. In the fullest form, the poduo or breaking of hell, the priest performs a ritual assault on the underworld: the walls, represented by tiles or a paper structure, are smashed with a sword and the soul is led out. This is the economic foundation of the Zhengyi clergy, who are married householders performing services for fees, and it is the single most common Taoist ritual anyone will actually attend. Hong Kong's urban Zhengyi tradition formally distinguishes red rituals for auspicious occasions from yellow ones for funerals, and different priests specialise.