The situa or citua (in Quechua situwa raymi) was the health and ritual purification festival in the Inca Empire. It was held in Cusco, the capital of the empire, during the month of September on the day of the first moon after the spring equinox, which in the southern hemisphere takes place normally on September 23. It was a very important festival whose rites are well described by the early Spanish chroniclers, in particular Cristóbal de Molina, Polo de Ondegardo and Inca Garcilaso de la Vega. The latter witnessed situas as a child after the Spaniards had reduced them to memorials of the actual Inca festival. The situa is also mentioned by Bernabé Cobo, who copied, most probably, its text from Molina,[1]: xxii Felipe Guaman Poma de Ayala, Pedro Sarmiento de Gamboa and Juan de Betanzos.
The festival was held when the rain season had just begun and many illnesses tended to occur. Rituals to the Creator-god were thus executed both in Cusco and in other lands conquered by the Incas in order to purify them and "send the evil away".[1]: 30
The four days rites included offerings "rams" (that is llamas and alpacas), carefully chosen for their white color, to the deities,[2]: Ch VIII purification by bathing in the river water, lighting large straw torches (like large balls, called panconcos) and preparing and eating the ritual maize buns called sanco (sankhu in Quechua)[3]: sankhu whose dough was often mixed with blood. All were allowed to drink chicha (fermented beverage, corn beer) during the four days festival «without stopping».[2]: Ch VIII A great number of persons and beasts gathered in the main plaza of Cusco (Haucaypata), which in Inca times was much larger than the current Plaza de Armas. Figures of the deities from the huacas (shrines) were carried to their respective temples they had in Cusco.
To obtain proper cleanliness of the city, all foreigners and with those with physical defects were banished from the city for a distance of two leagues.[1]: 31
According to Molina, Pachacuti Inca was the sovereign who defined the way the festival had to be performed, giving rules to an ancient tradition.[1]: 50