Kokugaku (Kyūjitai: 國學/Shinjitai: 国学; lit. National study) was a National revival, or school of Japanese philology and philosophy originating during the Tokugawa period. Kokugaku scholars worked to refocus Japanese scholarship away from the then-dominant study of Chinese, Confucian, and Buddhist texts in favor of research into the early Japanese classics.
What later became known as the kokugaku tradition began in the 17th and 18th centuries as kogaku ("ancient studies"), wagaku ("Japanese studies") or inishie manabi, a term favoured by Motoori Norinaga and his school. Drawing heavily from Shinto and Japan's ancient literature, the school looked back to a perceived golden age of Japanese culture and society. They drew upon ancient Japanese poetry, predating the rise of the feudal orders (in the mid 12th century) and other cultural achievements to show the 'emotion' of Japan. One famous 'emotion' appealed to by the kokugakusha is 'mono no aware'.
The word 'Kokugaku', coined to distinguish this school from kangaku (Chinese studies), was popularized by Hirata Atsutane in the 19th century. It has been translated as 'Native Studies' and represented a response to Sinocentric Neo-Confucian theories. Kokugaku scholars criticized the repressive moralizing of Confucian thinkers, and tried to re-establish Japanese culture before the influx of foreign modes of thought and behaviour.
Eventually kokugaku thinkers succeeded in gaining power and influence in Japanese society. Later, their thought influenced the Sonnō jōi philosophy and movement. It was this philosophy, amongst other things, that led to the eventual collapse of the Tokugawa in 1868 and the subsequent Meiji Restoration. In addition state Shinto and state socialism developed from kokugaku thought and thus indirectly led to Japan's imperialist expansion throughout the late nineteenth and early to mid twentieth centuries.
According to David Margarey Earl, the Kokugaku held that the Japanese national character was naturally pure, and would reveal its splendour once the foreign (Chinese) influences were removed. The "Chinese heart" was different from the "true heart" or "Japanese Heart". This true Japanese spirit needed to be revealed by removing a thousand years of negative Chinese learning.
- Earl, David Margarey, Emperor and Nation in Japan, Political Thinkers of the Tokugawa Period, University of Washington Press, 1964, pp. 66 ff.
- Earl, David Margarey, Emperor and Nation in Japan, Political Thinkers of the Tokugawa Period, University of Washington Press, 1964, pp. 67
- Harry Harootunian: Things Seen and Unseen: Discourse and Ideology in Tokugawa Nativism. Chicago: University of Chicago Press 1988.
- Mark McNally: Proving the Way: Conflict and Practice in the History of Japanese Nativism. Cambridge, MA: Havard UP, 2005.
- Peter Nosco: Remembering Paradise. Nativism and Nostalgia in Eighteenth Century Japan. Cambridge, MA: Havard UP, 1990.
- Michael Wachutka: Kokugaku in Meiji-period Japan: The Modern Transformation of 'National Learning' and the Formation of Scholarly Societies. Leiden, Boston: Global Oriental, 2013.
Notable Kokugaku scholars 
- Hagiwara Hiromichi
- Hirata Atsutane
- Kada no Azumamaro
- Kamo no Mabuchi
- Katori Nahiko
- Motoori Norinaga
- Motoori Ōhira
- Motoori Haruniwa
- Nakane Kōtei
- Ueda Akinari
- Date Munehiro
- Fujitani Mitsue
- Tachibana Moribe