What is the BEST term for the aboriginal Japanese mythology?

The best term for the aboriginal Japanese mythology is Shinto. Shinto is the indigenous spirituality of Japan, encompassing the beliefs and practices centered on kami (spirits or deities) and the worship of ancestors. It is deeply intertwined with Japanese culture and historical narratives, reflecting the natural elements, agricultural practices, and social structures evident in early Japanese society.

While Ainu refers to the indigenous people of northern Japan and their own distinct culture and beliefs, it does not encompass the broader mythological practices that are traditionally recognized in Japan. Yokai refers to a class of supernatural entities or monsters within Japanese folklore, and while they are significant within the mythological landscape, they represent only a part of a much larger system of beliefs. Samurai are historical warriors celebrated in Japanese history, but they are not related to the mythological definitions of spiritual practices or deities.

Shinto as a term encapsulates the entire framework of beliefs that incorporates the mythology and rituals practiced from the earliest days of Japanese civilization, making it the most fitting choice for describing the aboriginal mythology of Japan.