While the definition of "new religion" varies among scholars and religious groups, the term is generally used for groups founded sometime between the mid-19th century, when Japan started modernizing, and the mid-1970s.

Religious groups founded after the 1970s, such as Kofuku-no-kagaku (Institute for Research in Human Happiness), are sometimes referred to as "new-new religions."

Many religions founded before the war were persecuted by authorities during the war and prewar years, a period in which state Shintoism was pushed. In the postwar years, however, new sects have emerged in abundance.