There were many different variants of Fukko Shintō, but what generally united them was a desire to return to a worldview unique to the Japanese people, and which predated the influence of foreign teachings such as Confucianism and Buddhism.
Scholars such as Kamo no Mabuchi and Motoori Norinaga first advanced the theory of Kodō, followed by Hirata Atsutane and Honda Chikaatsu [ja] who completed Fukko Shintō through rejection of Confucianism and Buddhism, and fervor for what they saw as Japan's pure and ancient beliefs.
It had great influence on the imperial loyalists at the end of the Edo period, and after the Meiji Restoration it was introduced as part of the Sonnō jōi (revere the emperor, expel the barbarians) movement's ideology.
As the Buddhist sects Tendai and Shingon developed at the end of the Heian period, they were no longer merely coexisting, but a syncretistic blending of the religions began to take shape.
During the Edo period, Kamo no Mabuchi drew attention to the existence of ancient Shinto in his book "Kokuikō", and Motoori Norinaga, taking note of this, then completed his major work "Kojikiden", a commentary on Kojiki.
Hirata also carried out prominent research on subjects related to the spirit world, such as the realm of the dead and the soul, and put forward his own version of kokugaku, which referred to other religious groups such as the hokke sect, Vajrayana, Christianity and Daoism.