In Japan the vernal and autumnal equinoxes, commonly called o-higan お彼岸, are regarded as times when spirits of the dead return to the world of the living. Many people visit their family graves and/or make special offerings to ancestral spirits at the buddha altars (butsudan 佛壇) in their homes. Buddhist temples hold equinox assemblies (higan e 彼岸會) that feature offerings to spirits (shōrei kuyō 精靈供養). The term higan, literally the "other shore" or "opposite bank" of a river, entered the vocabulary of East Asian Buddhism as a metaphor for nirvana, that place of respite on the "other side" of sasāra, the torrent of birth and death. In Japanese usage, however the "other shore" is the realm of the dead, a place that is not necessarily free from suffering.