The website of the Nichiren Mission of Hawaii has a three long pages devoted to its history. Part 3 (of 3) recounts the changes after the end of World War II. Here are some excerpts I found interesting about adapting Japanese Buddhism to American Christian worship practices.
Chronologically speaking, the second half of the 100 year history of the Nichiren Mission of Hawaii begins with the 50th Anniversary celebration of the birth of Nichiren Buddhism in Hawaii. It is more practical, however, to draw a line in 1946, when Bishop Mochizuki returned from the relocation camp on the mainland U.S.A. and re-opened the Mission. The year marked the end of the Japanese-style and the beginning of the American-style Nichiren Mission of Hawaii. The impact of the war made the change inevitable.
The Japanese living in Hawaii and their descendants who had never been forced to choose between Japan and America, were forced to do so by the Pacific War. Most of them, quite naturally, chose to be Americans. The psychological change caused various changes in the Japanese American society such as the disappearance of Japanese kimono from the group pictures of temple events. Cut off from the roots in Japan, even Japanese Buddhist ministers changed—from sectarian to interdenominational in outlook. English began to replace Japanese in family conversation. Culturally, they have become Americans rather than Japanese.
On the other hand, as the constitutional freedom of religion and assembly was restored to Japanese Americans after the war, many of them flocked to the Buddhist temples and Shinto shrines, reacting to the religious suppression during the war years.
In the mind of those who flocked to the Buddhist temple, however, there was a subtle change. They felt like seeking refuge in Japanese Buddhism while refuting things Japanese. As a result, they were drawn by the un-Japanese Americanized Buddhism.
A positive effect of the Pacific War on Japanese Buddhism in Hawaii was the consolidation of inter-denominational friendship among Buddhist priests. Almost all Japanese Buddhist priests in Hawaii were sent to relocation camps on the mainland U.S.A. Living together as virtual prisoners in the confinement of these camps for several years required them to stand together. The solidarity among them resulted in the establishment of the Hawaii Buddhist Council to work together actively in the postwar years….
Activities of the temples were Americanizing in many ways: songs in praise of the Buddha were sung at Sunday School; sermons were given in English; and the Young Buddhist Association (YBA) was organized. On Sundays, services were performed in both English and Japanese. Prior to the war, Sunday services were held weekly but only a few members participated in them with most members preferring to visit the temple only for traditional services, such as ohigan and obon. However, as the temple activities became Americanized, members who visit the temple every Sunday increased and it became customary for everything to be carried out on Sundays. Also, under the auspices of the Hawaii Buddhist Council, joint services of the member temples became established as annual events.
Priestly costume also changed. Except for formal services such as ohigan and obon priests at that time wore a robe and stole over a white shirt, black tie and trousers in black. Today this habit has been abandoned except for the priests of the True Pure Land School.
Even the entertainment after special services became international from Japanese. A famous Korean dancer, Ms. Halla Pai Huhm, who became a temple member during Bishop Mochizuki’s tenure, performed traditional Korean dances with her disciples after the annual services for ohigan and obon.