The other important person Kumagusu met in London was Dogi Hōryū, who later became the leading Shingon Buddhist priest of the highest level. Kumagusu and Hōryū formed a lifelong bond.
The two were of a kindred spirit. In London they discussed aspects of world religions, and afterward they kept exchanging an enormous quantity of correspondence.
Kumagusu’s letters to Dogi Hōryū are considered among his most important academic works. In contrast to the principle of causality of the Western modern science, Kumagusu adopted the idea of random chances and expressed the nature of the universe through an aspect of esoteric Buddhism: the mandala (a visual expression of the Buddhist view of the world). This was the “Minakata Mandalas.”
Minakata’s theory seems to suggest some similarity with the prospect of the modern scientific theories.