In the book "Kata – The true essence of Budo martial arts?" Simon Dodd and David Brown state that "Bushido spiritualism" lead the martial art 'Bujutsu' to evolve into modern 'Budō' (武道). For their analysis, they review the Kamakura period to reiterate the influence Bushido held in martial arts evolution. They distinctly state, "For clarity any reference to bushido is in relation to bujutsu within the Kamakura to pre‐Meiji restoration period (pre-1868), and any links to budo are referring to the modern form of the martial arts." To supplement this affirmation Dodd and Brown discuss the variance between the meaning behind Bujutsu and Budo. According to Todd and Brown Budo is a redevelopment of traditional Kamakura period martial arts principles; Budo defines the "way of the warrior" through roots in religious ethics and philosophy. The martial art form's translation binds it to Confucian and Buddhist concepts of Bushido: