On page 111, Ma Aku talks about "bad juju" related to Kojo's job. This "bad juju" is most likely referencing to?

"Bad Juju" is most likely referring to Triangular Trade. the shipping business, and the way that slaves were transported. Ma Aku views the business as evil.

He loved the look of those boats, loved that his hands helped build and maintain them, but Ma Aku always said it was bad juju, him and all the other freed Negroes working on ships. She said there was something evil about them building up the things that had brought them to America in the first place, the very things that had tried to drag them under.