As a career diplomat, 60-year-old Masato Kitera knows the weight of his new position as Japan's ambassador to China, a post he took up in December.

Four months ago, the embassy was surrounded by Chinese protestors angry about the dispute over Diaoyu Islands, which the Japanese call the Senkakus. At that critical time, the new ambassador, Shinichi Nishimiya, died unexpectedly three days after his appointment was made public.