Originally samurai from the Chosu Clan of Japan, the shishi, or "men of spirit", were a faction who wanted to restore Emperor rule and break the Tokugawa Shogunate.  They espoused the political philosophy of Sonnō jōi (尊皇攘夷, "Revere the Emperor, Expel the Barbarians") originated by Seisisai Aizawa. 
Their view of "spirit" was complex, but certainly included the concept of kokutai, or the Japanese national polity for which the Emperor was father figure, and sometimes a deity. As such, the shishi were predecessors of the Japanese militarism of the 20th century.
- Merion and Susie Harris (1991), Soldiers of the Sun: the Rise and Fall of the Imperial Japanese Army, Random House, pp. 12-14
- William Theodore De Bary, Sources of Japanese tradition: From earliest times to 1600, Volume 1, Columbia University Press, p. 618
- Mikiso Hane (1990), Premodern Japan: a historical survey, Westview Press, ISBN 978-0813380650, pp. 214-217
- Marcel Thach, Sonno-Joi, Samurai Archives