In 1982, Father Valentine D'Souza arrived at St. Ignatius Church in Yotsuya with a sense of mission: As the first Indian national sent to minister in Japan, he believed it was his responsibility to provide an inclusive place of worship for foreign residents of the world's largest city. His early attempts to establish a congregation coincided with Japan Inc.'s increasing need for migrant labor and a corresponding first wave of immigration from Africa. In D'Souza's words: "There were certainly a lot of Africans."

D'Souza noted early on that African congregants were socially isolated, so he made church rooms available for Africans-only meetings — meetings that leaders in Japan's Nigerian and Cameroonian communities now credit for coalescing their civic organizations. He enabled Africans to attend the English-language Christmas Mass (held at midnight) by inviting parishioners to sleep in the church. When he learned Africans were delaying marriage to their Japanese partners because they couldn't afford a reception, he made the church's hall available. He asked only one thing of newlywed expats: that they begin attending Mass in Japanese. For the sake of their future children, they'd need to learn the language and, more than that, to integrate.

When D'Souza left the church in 2004, its foreign congregation had grown larger than its Japanese counterpart. Several of the programs he instituted persist, including a professionally staffed Japanese literacy program. Many of the African immigrants whose marriages he performed and whose children he baptized — including current Nigerian Union President Kennedy Fintan Nnaji — have emerged on the other side of the struggle for integration D'Souza hoped to help them weather.