The social and spiritual lives of the Lega people, are governed by a central initiation society known as Bwami; Bwami is responsible for teaching morality through community performances, dances and objects. The Bwami association includes 5 society grades including:
- Bwali (meaning 'circumcision'; the prerequisite association for joining Bwami where initiates are circumcised (between the ages of 12 and 20) and are thought lessons on the values and behaviours expected to Bwami members);
- Kongobulumbu the lowest grade of Bwami followed by a short ceremony where recently circumcised initiates are given even greater knowledge about the association;
- Ngandu is the highest grade in some communities (of which bombwa is the female equivalent);
- Yananio level consists of two sub-groups, the musagi wa yananio and the lutumbo iwa yananio (bulonda is the female equivalent) and,
- Kindi which is the most senior level of Bwami, sub-divided into three grades, kyogo kya kindi, musagi wa kindi and finally lutumbo iwa kindi. Bunyamwa is the equivalent kindi grade for women.
A Lega man must pass through all (voluntary) initiation societies respectively to be considered a rounded man with full insight into ancestral teachings and traditions. The Bwami association is also believed to strengthen bonds within the community.
Each initiation society has its own associated objects and sculptures (isengo, pl. masengo meaning ‘heavy things’) including the kisumbi stool owned by yananio and kindi initiates. The stools are used at Bwami ceremonies to demonstrate the high level rank of initiates within the most senior levels. "At the Bwami rite of kisumbi, which bears the same name as the stool, the focus of the ceremony is the stool itself. Every aspect of the stool refers to Bwami values. The smooth surface, achieved by sanding with special leaves, is compared to the transformation of initiates through Bwami teachings from rough, unformed beings to people who are considerate and wise (or "smooth"). The double circular seat and base refer like janus objects to penetrating sight and wisdom, and to the links between husband and wife, initiate and teacher."1 Once received, the stool is kept by its owner until death, after which it is handed over to the initiate's replacement in the Bwami association.
- Carved from a single piece of light wood (muntonko wood)
- Low to the ground like a bench
- Average height = 4" to 5"
- Slightly concave circular seat
- Seat of some stools decorated with circular copper nail-heads
- Otherwise stools not embellished with any design
- Slightly convex stool bottom (almost same diameter as seat)
- Stool without back or arms
- Four supporting legs between seat and stool bottom
- Each bending outward to form an angle
- Sometimes two central conically shaped protrusions In open space between legs - one facing downward from the seat, the other facing upward from the base
- Surface of stool is smooth, glossy and well patinated
- Colour of stools range from light to dark brown up to black
- Adze marks evened out with sandpaper leaves
- Markings remain on the underside of base