A tradition with its own logic
Ifa is a religious and divinatory tradition of the Yoruba people, whose homeland lies mainly in south-western Nigeria and neighbouring parts of Benin and Togo. It also spread through the Atlantic slave trade and is practised in modified forms in places such as Cuba and Brazil. Its central figure is Orunmila, a deity associated in Yoruba tradition with wisdom and with the knowledge held in Ifa. UNESCO has recognised the Ifa divination system as part of the world’s intangible cultural heritage.
This article looks at one feature of Ifa: the way it generates a fixed set of 256 figures called odu. These are described here as part of a religious tradition, as its practitioners understand it. Describing the structure does not imply that divination can foresee events, and nothing here is guidance for decisions.
How a figure is made
The Yoruba diviner is called a babalawo, often translated as “father of secrets”, although there are also female priestesses in related roles. Two main methods are described in published accounts.
The more elaborate method uses sixteen palm nuts, called ikin. The diviner passes them from one hand to the other, and the number left in the hand is either one or two. Each outcome is recorded as a mark, a single stroke or a double stroke, in a wooden tray dusted with fine powder. Repeating the action builds a figure from marks arranged in two columns.
The quicker method uses a divining chain, the opele, with eight half-shells or seed pieces, four on each side of a central cord. When the chain is thrown, each piece lands with one of two faces up, concave or convex. The result is again a set of eight marks in two columns of four.
In both methods, each mark has only two possible values. That is why the system is often called binary-like.
The arithmetic of 256
Each column of four marks can take 2 x 2 x 2 x 2 = 16 patterns. A full figure joins a left column and a right column, so the number of possible figures is 16 x 16 = 256. The same result follows from counting eight two-valued marks: 2 to the power of 8 is 256.
The sixteen figures in which the two columns are identical are known in Yoruba as the principal odu, sometimes translated as the major or “mother” figures, and each carries a name. The other 240 are combinations of two different principal figures and are often described as their offspring. Check: 256 minus 16 is 240. Names and spellings vary by region and by the writer, so this article avoids a full list.
Verses, not just patterns
The numbers are only the frame. What gives an odu its meaning, in the tradition, is a body of verses called ese Ifa. These are memorised poems, stories and proverbs attached to each figure. A diviner learns very many of them over a long apprenticeship, and the corpus is oral, with versions that differ between lineages and towns.
In practice, accounts describe the diviner identifying the figure and then reciting verses that belong to it. The client is expected to listen for a passage that seems relevant, and the discussion that follows is at least as important as the figure itself. The tradition also attaches advice about offerings and conduct to the verses. These are religious practices, and different practitioners emphasise different parts of them.
The comparison with binary notation
It is tempting to see Ifa as an early computer. The comparison with binary notation is fair at one level: both rely on two states combined in a fixed number of places. But the resemblance is structural, not historical. There is no evidence that Ifa influenced the modern binary arithmetic described by Gottfried Leibniz in the seventeenth and eighteenth centuries. Leibniz is better known for noticing, after he had worked out his system, a resemblance to the hexagrams of the Chinese I Ching, which are also built from two kinds of line.
The meanings differ as well. In arithmetic, a string of binary digits stands for a quantity. In Ifa, a string of marks is a name that opens a store of verses. Both systems are combinatorial, but they were built for different purposes.
Related systems and open questions
Neighbouring peoples have similar systems. The Fon of Benin, for example, are described as using a close relative of Ifa under the name Fa. Scholars have also discussed possible links between West African figure-based divination and the medieval Islamic practice of geomancy, which used sixteen figures built from lines of dots. Whether one influenced the other, or whether there were exchanges in both directions, is debated, and no firm consensus can be reported here. Given the oral nature of Ifa, it is also difficult to date its structure.
Counting itself is part of the broader Yoruba picture. The Yoruba number words are famous among linguists for their use of subtraction and for twenty as a building block, a feature covered under base twenty counting. That is a language feature rather than a part of Ifa, and it should not be confused with the sixteen-based structure of the odu.
Putting it in perspective
Ifa is a living religion with a large number of followers, a long oral literature and a formal training. The 256 figures are a tidy way to summarise one aspect of it, but they should not be mistaken for the whole. For outside readers, the most reliable approach is to separate three things: the mathematical structure, which is easy to describe and verify; the religious meaning, which belongs to the tradition; and any claim that divination can reveal the future or settle personal choices, which is a matter of belief that this article does not endorse.