Fujii was born into a peasant family in the wilderness of the Aso caldera. At the age of 19, he was ordained a monk in the unusually ascetic and intellectual tradition of Hōon-ji in Usuki, Ōita. He started missionary activities in Manchuria in 1917 but the Great Kanto earthquake made him return to Japan in 1923. Reading of Nichiren's declaration that the Lotus Sutra would one day be preached in India, he decided to go there. He arrived in Calcutta in January 1931 and walked throughout the town chanting the daimoku and beating a drum, a practice known as "gyakku shōdai".