 With his legal background and Tokyo University credentials, he was often offered more lucrative posts within the central government, but he always refused as this would rob him of time to write.In 1966, Saitō was awarded the 12th Edogawa Rampo Prize for his mystery novel  He followed on this with several best-selling mystery series, creating the "Tarot Himeko series", the "Inspector Edogawa Murder-Travel series", and the "Inspector Kobayakawa series", which were the basis for several popular television series.Saitō is known for his tremendous creative speed, at times producing several hundred pages of work a week, or completing a novel within the span of a month.