In 1999, Hiroo graduated at age 25 from the Ministerial Training School in Japan, and one of the instructors encouraged him to serve in a foreign field.
Pada 1999, Hiroo lulus dari Sekolah Pelatihan Pelayanan di Jepang pada usia 25 tahun. Salah satu pengajarnya menyarankan agar ia melayani di ladang asing.