Buddhism has been a missionary religion from its beginning. Japan was among the countries where this “foreign” religion arrived and was assimilated, adapted, and reshaped into new forms specifically connected to the new geographical and cultural environment. Buddhism traveled long distances from India through China and Korea, bringing with it flows of people, ideas, technologies, material cultures, and economies. More than ten centuries after its arrival in Japan, the first phase of propagation of Japanese Buddhism started and was linked to the history of Japanese migrants to Hawaii, North America, and Brazil since the 19th century. This was a history of diaspora, a term that implies not only the physical—and often traumatic—dispersion of people who left their homes for unknown places, but also a reconfiguration of their identities through the adaptation to these new places and their cultures. The main role of Buddhist priests sent from Japan was to assist and provide comfort to the newly formed communities of migrant laborers, who very often experienced racial discrimination and lived under harsh conditions. Temples became important loci of Japanese community life, as well as centers for the preservation of Japanese culture. Diasporic communities felt the urge to keep a bond with the homeland and a reconnection with some past traditions, while, at the same time, striving toward integration in the new society. Japanese Buddhist denominations in diasporic communities had therefore to accommodate different needs and adjust their teachings and practices to better suit their host cultures. Some of them underwent substantial changes, while others placed more emphasis on some practices instead of others. Moreover, Japanese Buddhist schools had to find a way to balance between their traditional role in Japan, which was—and still is—closely related to funerary rituals and memorials, and the new stimuli and requests coming from the new generations of Japanese migrants (nisei and sansei) and the non-Japanese spiritual seekers, the latter mostly interested in meditative practices and not in funeral Buddhism. In short, what needed to be done was to overcome a status of “ethnic” religion without, however, losing its own identity.