Hideo Yokoyama (横山 秀夫) worked as an investigative reporter with a regional newspaper north of Tokyo for 12 years before striking out on his own as a fiction writer. He made his literary debut in 1998 when his collection of police stories Kage no kisetsu (Season of Shadows) won the Matsumoto Seicho Prize; the volume was also short-listed for the Naoki Prize. In 2000 his story Doki (Motive) was awarded the Mystery Writers of Japan Award for Short Stories. His 2002 novel Han'ochi (Half Solved) earned a Konomys No. 1 and gained him a place among Japan's best-selling authors. He repeated his Konomys No. 1 ranking in 2013 with 64 Rokuyon (64), his first novel in seven years. Other prominent works include his 2003 Kuraimazu hai (Climber's High), centering on the crash of JAL Flight 123 that he covered as a reporter in 1985; the World War II novel Deguchi no nai umi (Seas with No Exit, 2004); the police novel Shindo zero (Seismic Intensity Zero, 2005); and the story collection Rinjo (Initial Investigation, 2004).