Roald Knutsen was born in Hertfordshire of Anglo-Norwegian parents and educated at The Perse School, Cambridge, and Watford Grammar School. After studying Art and Design he served as a regular in the Intelligence Corps and followed with a successful career in graphic design, choreographing complex medieval combat sequences for a computer film project in England and the USA, and writing. For the past half-century he has practised traditional Kenjutsu, Kendo, Iai-jutsu, and So-jutsu under a succession of famous Japanese masters, having menkyo-kaiden (senior master's licence), in one of the oldest transmissions of Iai-jutsu, and the rank of 6th dan Renshi in Kendo. He has researched and written extensively about the Japanese warrior traditions and aspects of Japanese history. His is also the author of Japanese Polearms (1963), Rediscovering Budo (2004), and Japanese Spears (2004), which he co-authored with his wife Patricia Knutsen.