The best documentation of the chacapa comes from Luis Eduardo Luna's work in the 1980s among vegetalistas, the plant specialists of the mestizo river towns of the Peruvian Amazon around Iquitos. That setting is worth being precise about, because it is routinely misdescribed. Vegetalismo is not an untouched forest tradition. It is an urban and riverine practice that grew out of indigenous, African-descended and Iberian folk elements in a region reshaped by the rubber boom, and it has been in contact with the wider world for its entire existence.
Luna recorded practitioners who named their teachers, described their apprenticeships, and worked in towns with patients who arrived by boat. The chacapa sits in that world: a cheap made object in a practice that was already, when it was described, thoroughly mixed and thoroughly modern.
Since then the instrument has travelled a very long way. The international spread of ayahuasca practice from the 1990s onward carried the chacapa with it, and leaf rattles are now sold worldwide, made in the Peruvian Amazon for export and made elsewhere in imitation. Whether that is continuity or something else is a live argument among the people who work with it, and it is not one this atlas will settle.