The batan is a kitchen utensil used to process different kinds of foods in South American Andean cuisine. It has a flat stone (the batan proper) and a grinding stone called a uña. The uña is held in both hands and rocked over the food in the batan. Depending on the process wished, the uña's weight is slightly held back, let loose over, or pressed on. The rocking movements also vary depending on the procedure. The grinding is done dry or with water or oil.
In Andean households many different dishes are prepared in this manner, in rural and urban areas. The most important use it has is for preparing llajwa. For many Bolivians, Peruvians, Ecuadoreans and Colombians it's not the same when done in a blender.
It is also used to husk grains, wash quinoa from its alkaloid (saponin), grind grains, crush papa lisa and even to prepare small quantities of flour.
The use of the batan is so widespread that you will find it in a smaller form among the kitchen appliances in Bolivia in any modern La Paz apartment building, and in many rural zones of Peru, Ecuador and Colombia.
It is also used in India, in large number of households. It is known as "Sil-Batta" in Hindi with Sil referring to flat stone and Batta referring to a cylindrical grinding stone. It is known as Pata-Varvanta in Marathi and used in the state of Maharashtra. These grinding stones are primarily used to prepare chutney and masala for cooking and occasional use including grinding soaked lentils in preparation for dosa/vadas and papadum.