Graduated from Shinshû University, where he majored in economics. A nonfiction writer; became the youngest-ever winner of the Ôya Sôichi Nonfiction Prize in 1999 for Toki no yuigon (The Testament of the Toki [Japanese crested ibis]). His other works include Ken’ekikan (Quarantine Officer) and Jukunen sei kakumei hôkoku (A Report on the Sex Revolution Among the Mature-Aged).