The Autumnal equinox also occurs in the middle of Higan . In Japan , the equinox falls in the middle of a week-long period known as Higan ( お彼岸 ) , which is observed as a Buddhist holiday , and families return to their ancestral homes to visit and clean the graves .
О-Хиган — семидневный период , который включает три дня до равноденствия и три дня после .