Zazen (坐禅; Chinese: zuò chán pinyin or tso-chan Wae-Giles) is at the heart of Zen Buddhist practice. The aim of zazen is just sitting, opening the hand of thought. This is done either through koans, Rinzai's primary method, or whole-hearted sitting (shikantaza), the Soto sect's method. (Rinzai and Soto are the main extant Zen schools in Japan; they both originated in China as the Linji and Caodong schools, respectively.) Once the mind is able to be unhindered by its many layers, one will then be able to realize one's true Buddha nature. In Zen Buddhism, zazen (literally "seated meditation") is a meditative discipline practitioners perform to calm the body and the mind and experience insight into the nature of existence and thereby gain enlightenment (satori).