Based on the works of Hakuin Ekaku 白隱慧鶴 (1686–1769), this article analyses the practice system he constructed and its background and clarifies the following two conclusions. First, the system of practice demonstrated by Hakuin involves focus on one specific kind of practice to achieve ‘seeing one’s nature’ (kenshō 見性), and then ‘practice after insight’ (gogo no shugyō 悟後の修行). Among them, ‘practice after insight’ consists of two parts: ‘seeking bodhi above’ (jōgu bodai 上求菩提) by constantly consulting kōan cases to refine one’s own realisation, and ‘cultivating sentient beings below’ (geke shujō 下化眾生) by guiding other people through giving dharma teachings. Second, the core of Hakuin’s practice system is the three essential elements consisting of ‘insight,’ ‘seeking bodhi above,’ and ‘cultivating sentient beings below.’ The background against which they formed was the three enlightenments obtained in Hakuin Ekaku’s life.