Many Vietnamese students came to Japan in the early 20th century. Japan allowed more to come as refugees after the Vietnam War. Vietnamese workers came to Japan in the 1990s to earn better salaries. Many Vietnamese refugees change to permanent residential status to be able to have a better life in Japan. Some bring their families to Japan in what is called chain migration.
Most Vietnamese in Japan live in Tokyo and the Kanto region and also in Greater Osaka.

They speak Vietnamese and Japanese. It has been difficult for the Vietnamese in Japan to find adequate work. They are handicapped by their lack of Japanese language skills. There are cultural difficulties. There are famous Vietnamese people living in Japan.

The earliest forms of Vietnamese worship were animism and veneration for ancestors. The Vietnamese worshiped the sun, soil, water and the earth fertility goddess Mau. The Vietnamese believed that spirits dwelt in the mountains, rivers, rocks, and other forms of nature. There were also spirits of their departed ancestors who needed to be placated and honored.
Later Buddhist, Taoist, and Confucianism thought made their way to Vietnam. These beliefs were incorporated into the Vietnamese form of animism and ancestor veneration. No matter where they live, it is common for the Vietnam to practice Buddhism blended with their old spiritual practices.
About one out of 12 Vietnamese claim to be followers of Jesus Christ. Most of these are Roman Catholics with a much smaller Protestant church.

The Vietnamese must see that Christianity is not a foreign religion imposed on them by outsiders. They need to see the love of Christ lived out among them by Spirit-filled disciples.

Pray that the difficulties the Vietnamese are having in Japan will lead them to Jesus Christ.
Ask the Lord to send loving disciplers to the Vietnamese wherever they live.
Pray for a spiritual hunger among the Vietnamese that drives them to read the Bible and listen to Christian radio programs.
Pray for a church planting movement that affects every Diaspora Vietnamese community.

Scripture Prayers for the Vietnamese in Japan.

quora.com/What-is-the-main-religion-in-Vietnamquora.com/What-is-the-main-religion-in-Vietnam
https://en.wikipedia.org/wiki/Vietnamese_people_in_Japan
https://e.vnexpress.net/news/news/vietnamese-in-japan-concerned-about-high-crime-rates-among-compat