Or o-harai, o-barae-shiki. 'Ceremony of great purification'. A form of harae rite based on the oharae norito in the Engi-shiki, also known as the Nakatomi no harae after the Nakatomi clan who were authorised to recite it. An o-harae is now performed in the imperial household and at shrines throughout Japan twice a year on the last days of the sixth and twelfth months (June and December). The term is used for special end-of-year purification rites e.g. in companies. Individuals may also recite the oharae norito as a form of purificatory practice.
A Popular Dictionary of Shinto. Brian Bocking.