Born in Kyoto on January 24, 1619, Yamazaki Ansai was the son of a former rōnin-turned-doctor and the last of four children. In his youth, he was strongly influenced by both his mother and grandmother. While his mother urged him to develop a noble heart worthy of a samurai's son, his grandmother supported him in his study of the Chinese language. In his preteens, he was sent by his father to serve as an acolyte at a Buddhist temple on Mount Hiei. In his early teens, Ansai returned home, and after several years was finally permitted to enter the Myōshin-ji temple of the Rinzai Zen sect in Kyoto for further study. Due to his incredible scholarly aptitude, in his early twenties he was granted entrance to the Gyūkō-ji temple in Tosa. During his time at Tosa, he was strongly advised by his fellow monks to concentrate his studies on the teachings of Neo-Confucian scholars, thereby beginning the process of Ansai's conversion to Neo-Confucianism and ultimate rejection of Buddhism. Ansai was particularly captivated by the writings of the Song dynasty scholar, Zhu Xi (Chu Hsi), which later became the basis of Ansai's moral philosophy/teachings. At twenty eight, he returned to Kyoto, and under the patronage of Nonaka Kenzan, was able to continue his Neo Confucian studies, as well as begin to publish his own materials. With the production of his first work Heresies Refuted (Heikii, 1647), an outright rejection of Buddhist faith, Ansai fully embraced the One True Way of Neo Confucianism.