We may understand the words Chukwu or Chineke to refer to God Almighty, but when we say only chi chi is not God, at least in the Pre-Christian understanding of the word by our forebears
The Photos below are of a Chi Shrine from Nkharahia, Ikwerre region of Rivers State,
At Nkharahia and the surrounding area chi shrines (obo chi/ ihu chi) were common, They consisted of a room the walls of which, both outside and in, are covered by grey coloured plates fixed in the clay, or decorated with elaborate patterns formed of cowries. An altar-like ridge along the rear wall supports the sacred emblems, while mud seats, smoothed to a pottery-like finish, bear offerings of china, glass, manillas, and food.
These chi shrines were common among the Etche- and Ikwerre (ishimbam), Oratta and parts of Mbaise,
a mans Chi is represented by three sticks, the central one half as high again as those to right and left, and a womans by four wooden fragments fixed in the clay filling of a small earthen bowl. To this emblem of their personal god every Igbo man, or woman, kills goat or fowl, at the time of the yam festival. The offering is avowedly made in thanksgiving for harvest and to entreat help and protection during the coming year.
Any individual could own a chi shrine of his own, it was usually owned by one family where every member of the family would have his own niche where he set up an altar to his own chi, children could inherit and honour the chi of their mother but not their father, men's chi leaves the world with them,
The priest of the chi shrine is usually the head of the family or the Ojiofor of the family, the priest of a chi shrine is usually referred to as Ezechi or Ezechukwu.
What then is chi?
Accodring to old Igbo belief Chi simply translates as Your Guardian Spirit, or your Spirit force, Chi is the spirit force that directs your individual destiny,
Every Igbo man has his chi peculiar to him, he believed that his chi guides his part and protects him,
In some circles it is also referred to as ehi,
That is why when something good happens to you or when u escape disaster, the Igbo say you have "chioma" or "ehioma" it means you have good luck or a fortunate destiny, chioma does not mean "good God" that's a naive layman's analogy. You also hear kelechigi when u miss a disaster, Kelechi did not mean thank God, it meant something like "thank your stars/luck" along the line of today's speech
Every Chi is believed to be a spark that emanated from the great Chi, the very first Chi who is known as Chukwu or Chiokike,
How did the concept of Chiokike arise? According to an Oratta legend, in the beginning was the first Chi the great spirit, Chi begat Ekeh his first child, and through Ekeh they created the entire universe and all that's within it, that is why they say Chi na Eke (Chi and Eke) not Chi na-Eke as many erroneously think,
It's an Igbo understanding of the Godhead, that consists of Chi and Eke, Agwu is the Divine force that creates a relationship between Chi and Eke and between the Godhead and his creation, Agwu conveys the message between Chineke and His Creation, Agwu is the connection between our individual chi and the great Chi, between the material realm and the spiritual realm and between God and man, thus Chi Eke and Agwu is the triune personality of the igbo concept of God!
There were also Agwu shrines, no one was allowed to touch that except the owner, devotion to Agwu was particularly popular in Ohafia-Aro axis.
I have always wondered why the igbo embraced the Catholic Church in large numbers even when the Anglican mission arrived first, it's because they recognized in Catholic theology and mysticism some similarities with their own mysticism.
Having said this, Igbo names such as Chinaza, Chidimma, Chibuzo Ebubechi etc are not native names but rather Christian names given erroneously because of the new Christian understanding of what Chi means, I think it started by abbreviation of Chineke or Chukwu to just Chi, now many think they mean the same thing, that is why such names were rare amongst our grandparents and great grandparents because they wouldn't mean the same thing they meant now to the people of those days back when igbo still had a better grasp of their culture and it was undiluted, Chukwu should be the correct affix to such names.
Reference : J. amoury Talbot (British anthropologist)