As an ancestor worship, one of the essences of Ancient Shinto, which is passed down to the present day through syncretization with Buddhism (syncretization of Shinto with Buddhism), the Obon festival (a Festival of the Dead or Buddhist All Souls' Day) is named (as a pure Buddhist event, the Urabon festival [a Festival of the Dead or Buddhist All Souls' day] worshiping the Buddha is held in the same period), and a dictionary explains that it is a festival for ancestor worship.
古神道の本質の一つでもある先祖崇拝が、仏教と習合（神仏習合）して現在に伝わるものとして、お盆（純粋な仏教行事としては釈迦を奉る盂蘭盆があり、同時期におこなわれる）があり、辞書の説明では先祖崇拝の祭りと記載されている。