Some of the oldest and most recognized koryū include the Tenshin Shōden Katori Shintō-ryū, founded in the 15th century, known for its extensive curriculum covering sword, staff, spear, and strategy techniques. The Kashima Shintō-ryū, also from the 15th century, is notable for its focus on fencing and its influence on the development of other Japanese fencing schools. Both schools emphasize the importance of spiritual development alongside martial skill, reflecting the integration of physical practice with samurai philosophy.