In the Middle Ages there was the realm of Tengu other than the six realms of Buddhism, which was assumed and interpreted as Avici for those who were not going to fall into Hell because they had learned Buddhism but were not going to Heaven either because they had done wrong.
中世には、仏教の六道のほかに天狗道があり、仏道を学んでいる為地獄に堕ちず、邪法を扱うため極楽にも行けない無間（むげん）地獄と想定、解釈された。