In 1867 Captain Brinkley returned to Japan, never again to return home. Attached to the British-Japanese Legation, and still an officer in the Royal Artillery, he was assistant military attache to the Japanese Embassy. He resigned his commission in 1871 to take up the post of foreign advisor to the new Meiji government, and taught artillery techniques to the new Imperial Japanese Navy at the Naval Gunnery School. He mastered the Japanese language soon after his arrival, and both spoke and wrote it well.