Edai Siabo, an ancestor of the western Motu village of Boera, is the culture hero credited with founding the hiri, the annual long-distance voyage by which the Motu carried earthenware pots westward to the Gulf of Papua and returned laden with sago. In the Boera tradition he was seized while fishing on the reef by a spirit of the sea, which drew him beneath the water and there taught him to build the lagatoi, the large multi-hulled sailing craft, and to undertake the voyage. He returned bearing knowledge of the expedition and of the sacred restrictions its success required, notably the taboos kept by the voyagers' wives at home. The narrative is recorded in the earliest systematic ethnography of the region and is still recited at Boera, where particular lineages claim descent from him. Sources differ on whether the encounter was a bodily abduction beneath the sea or a vision received in trance.