Otani attended the Peers School before he studied Chinese and Buddhist classics under keiun Maeda in Kyoto.
Otani traveled in Canton, Hankow and Peking in 1899. Late that year, he went to Britain via India, where he inspected charity works and religious institutions. He led a party of researchers in an expedition to Central Asia, India and China to explore the vestiges of ancient Buddhist culture.
Between 1900 and 1902, Otani, a Buddhist priest, lived in London studying Western theology and came into contact with a number of European explorers including Aurel Stein and Sven Hedin. Hedin had made his first expedition to Tibet in 1893, and had brought back a large number of documents from his second expedition, while Stein had recently completed his first expedition in the Taklamakan Desert. Having learned of the results of these expeditions, Ōtani decided to return to Japan by land via Tibet, with the intent of researching the spread of Buddhism through Central Asia.
After the news of his father's death in January, 1903, he returned to Japan and succeeded his father as Chief Abbot of the Nishi Honganji Temple, one of the head temples of the Shinshii Sect. He later sent a research party to Central Asia to resume the expedition. Ancient sutras and other valuable Buddhist data were collected by the party.
He retired as Chief Abbot for involvement in a financial scandal of his sect and devoted himself to linguistic study of Buddhist classics and industrial surveys. Otani established the Kojukai Society through which he published the results of his researches.