Dr. Hiroko Willcock (senior lecturer at Griffith University, Australia) explained "Koyo Gunkan is the earliest comprehensive extant work that provides a notion of Bushido as a samurai ethos and the value system of the samurai tradition." However, it does not have a set of principles regarded as "true" or "false", but rather varying perceptions widely regarded as formidable throughout different centuries. Emphasized by Thomas Cleary, "Confucianism, Buddhism, and Shinto were each represented by a variety of schools, and elements of all three were commonly combined in Japanese culture and customs. As the embodiment of Samurai culture, Bushido is correspondingly diverse, drawing selectively on elements of all these traditions to articulate the ethos and discipline of the warrior".