Jeffery and Akiko serve as catalysts to encourage multiplication in Japanese churches.

They coach and encourage church planters at the local, regional, and national levels, and Jeffery supports leadership development for Japanese pastors and planters. He also researches the churches of north-eastern Japan in the years since the triple disasters of 2011, drawing lessons that help church planters and Christians across the country.

Jeffery was first called to Japan as a university student on a short-term mission, and returned in 1995, meeting Akiko — a fourth-generation Japanese Christian from the Tokyo area — while on staff at a Tokyo-area church. They served on a church-planting team in Yamagata, then worked with three church-multiplication networks in Okinawa, before returning to the Tokyo area in 2014.