On December 8, 1970, Okumura was ordained at Antaiji by his teacher Kōshō Uchiyama, where he practiced until Uchiyama retired in 1975.
Pada 8 Desember 1970, Okumura diangkat di Antaiji oleh gurunya Kosho Uchiyama, diamna ia berpraktik sampai Uchiyama pensiun pada 1975.