Ifa is a system of divination based on sixteen basic and 256 derivative figures (odu) obtained either by the manipulation of sixteen palm nuts (ikin), or by the toss of a chain (o̧pȩlȩ) of eight half seed shells. The worship of Ifa as the God of Divination entails ceremonies, sacrifices, tabus, paraphernalia, drums, songs, praises, initiation, and other ritual elements comparable to those of other Yoruba cults; these are not treated fully here, since the primary subject of this study is Ifa as a system of divination. The mode of divination will be discussed in detail later, but a brief description is required at the outset.
The sixteen palm nuts are grasped in the right hand, leaving only one or two nuts in the left; if two nuts remain, a single mark is made on the divining tray; if one nut remains, a double mark is made. Repeating this procedure four times will give one of the sixteen basic figures as shown in Table 1, A; repeating it eight times gives a pair or combination of the basic figures, i.e. one of the 256 derivative figures. Alternatively, one of the 256 derivative figures can be obtained by a single cast of the divining chain, with heads and tails instead of odds and evens. The chain is held in the middle so that four half seed shells fall in a line on each side. Each half shell may fall either heads or tails; i.e. it may fall with its concave inner surface upward, which is equivalent to a single mark, or with this surface downward, equivalent to a double mark on the tray. Representing the concave inner side up as O and the convex outer side up as the sixteen basic figures (one half of the divining chain) appear as given in Table 1, B. The basic figures are listed in Table 1 in the order recognized at Ifȩ, but a slightly different order is more widely recognized (see Chapter IV, Table 3, B).
Ifa divination is practiced by the Yoruba and Benin Edo of Nigeria (Dennett, 1910: 148; Melzian, 1937: 159; Bradbury, 1957: 54-60; Parrinder, 1961: 148); the Fo̧n of Dahomey, who call it Fa (Herskovits, 1938: 201-230; Maupoil, 1943); and the Ewe of Togo, who know it as Afa (Spieth, 1911: 189-225). It is also practiced under the name of Ifa by descendants of Yoruba slaves in Cuba (Bascom, 1952: 170-176) and Brazil (Bastide, 1958: 104-109). The Fo̧n and Ewe acknowledge as its place of origin the Yoruba city of Ifȩ, from which the Yoruba themselves claim it has spread. It was at Ifȩ that the Ifa verses given in Part Two were recorded and that the system of divination was studied in greatest detail. Where information is based on field work in other Yoruba areas, or drawn from the literature, it is so specified.
Ifa divination may be practiced more widely than is indicated above. Thomas (1913-1914: I, 47) reports cryptically that the Ibo of eastern Nigeria "also have the well-known palm nut divination." The Kamuku and Gbari or Gwari are neighboring peoples in Niger Province, Northern Nigeria. Among the Kamuku, "to foretell the future, peas are shaken up in a tortoise‐ . . .