Thanks these are very interesting articles I will read. This is a complex subject and obviously even if the Portuguese had not enough "muscle" to carry a slave trade without local support they were no saints. As war was usually the way of increasing the number of captured slaves I read that in Brazil wars were promoted, (like if the natives were not enough warlike already), in order to increase the number of slaves being captured and sold by the natives.That particular claim in the wikipedia article on the Jaga is an interesting notion, and I have come across a similar claim elsewhere though I have not been able to track down the primary source for the idea (that the motivation for the Jaga invasion had to do with fighting against slaving operations from Kongo). Perhaps someone was drawing on something in a primary source when describing it as an anti-slave-trade invasion, but I have not been able to find the original source(s).
Several articles have been written about the Jaga, theorizing about who they really were, where they possibly came from, and what the motivation for their invasion was and it seems that so far their identity and the actual motivations behind their invasions are not exactly clear.
Of the articles that have been written about the Jaga, three of the most interesting are:
"Requiem for the "Jaga" " (1973) by Joseph Miller
"A Resurrection for the Jaga" (1978) by John Thornton
"The Jaga Reconsidered" (1981) by Anne Hilton
Miller argues that the Jaga were more of a construct, myth, or misunderstanding than an actual foreign invading group, while both Hilton and Thornton disagree with this idea and argue that the Jaga existed and were a real group, but give different identifications for who they were.