Achebe says that the story of how Chike’s father became Osu (or lower caste) is important “because even today when everything is upside down, such a story is very rare.” In fact, the story is not a digression; it is perhaps the only way to explain who Chike is. In one sense, Chike is a kind of outcast; his refusal to eat a yam offered by a neighbor is not only at odds with village etiquette, it is also symbolic of his parents’ rejection of traditional values and embrace of Christianity. By telling the story of how Chike’s father married an Osu “in the name of Christianity,” Achebe is suggesting that Chike is the product of a “mad marriage venture,” a kind of human cultural revolution.

The story of Chike’s father also points out the role of story in Nigerian culture and the clash of white ”rationalism” and African “superstition.” We learn that when Chike first goes to school he is worried about being whipped because of a song his sisters sang about school. However, Achebe explains that “one of the ways emphasis is laid in Ibo is by exaggeration,” meaning that the song is not meant to be understood literally. A similar case is when the grandmother, upset about Chike’s father’s decision to marry an Osu, visits the diviner to find out what will happen. The “prophecy” of the diviner is exactly what the current situation is. In other words, what the story says is not the same as what it means. This makes me wonder about the meaning or function of Achebe’s text as a whole. In the same way that Chike likes the word “periwinkle” for its “private” meaning, the inclusion of his father’s story has perhaps less to do with providing background information than suggesting another “private” meaning, one that has to do with the resistance of Nigerian culture to the logic of white storytelling. 

In the middle of the story, Chinua Achebe relates the circumstances surrounding the marriage of Chike's parents in order to provide us some sort of context for Chike's seemingly strange habits.

Accordingly, Chike and his family live in a traditional Nigerian village where children are regarded 'as the common responsibility of all.' One day, thinking to do him a kindness, a neighbor lady offers Chike, then four years old, a piece of yam. To her consternation, Chike resolutely rejects her gift, telling her that his family does not partake of 'heathen food.' Despite her anger, the woman marvels at the audacity of an Osu in rejecting her gift. At the time, the Osu were considered Nigeria's outcasts. They were forbidden to own land and to participate in common rituals. Upon death, Osu had to be buried on separate land, called the 'Bad Bush.' Anyone who married an Osu was considered an outcast as well (Chike's father, Amos, married an Osu woman despite not being an Osu himself); the children of such a union were also pronounced 'untouchable' and shunned by the general populace.

In the story, the neighbor thinks that the white man's presence in Nigeria has precipitated a state of affairs antithetical to traditional sentiment. To her, the fact that an Osu like Chike would be so bold as to reject a gift from a free-born Nigerian means that the white man has usurped the natural order of things in Nigerian society. She in incensed that an Osu would dare to put on such airs, considering that he is a lowly outcast.

So, Chinua Achebe tells us the story of Amos' marriage to explain Chike's seemingly strange, uncharacteristic behavior and attitudes (at least attitudes strange for an Osu child). He further states that the importance of knowing how Chike's father becomes an Osu cannot be underestimated, as such an occurrence is so rare. Achebe shows us that, just as Amos rejects traditional Nigerian concepts of class, so does his young son. Neither views himself as an outcast. Chike's anglicized view of both religion and education further highlights the fragmentation of Nigerian society and the conflict between the traditional and the new ways.