Chibalo was the system of debt bondage or forced labour in the Ultramar Português (the Portuguese overseas provinces in Africa and Asia), most notably in Portuguese Angola and Portuguese Mozambique (unlike most other European overseas possessions of the 20th century, the Portuguese ones were not considered colonies, but full-fledged provinces of Portugal proper).
In 1869 Portugal officially abolished slavery, but in practice, it continued nonetheless. Chibalo was used to build the infrastructure of the African provinces, as only Portuguese settlers and assimilados received an education, making them exempt from this forced labour.