Yupana
A yupana (from Quechua yupay: count) is an abacus used to perform arithmetic operations dating back to the time of the Incas.
Types
The term yupana refers to two distinct classes of objects:
table-yupana (or archaeological yupana): a system of trays of different sizes and materials, carved at the top of the device into geometric boxes, into which seeds or pebbles were placed, presumably for performing complex arithmetic calculations. The first of these tables was found in 1869 in the province of Cuenca (Ecuador) and marked the beginning of systematic studies on these objects. All archaeological finds are very different from each other.
yupana of Poma de Ayala: a picture on page 360 of El primer nueva corónica y buen gobierno written by the chronicler of the Indies Felipe Guaman Poma de Ayala, representing a 5x4 chessboard. The picture, although having some similarities with the majority of table-yupana, presents several differences from these, first of all, the shape of the boxes (rectangles), when those of table-yupanas are polygons of varying shape.
