Hakuin Ekaku’s emergence as a Zen master unfolded through a long, exacting journey rather than a single decisive moment. As a youth, he entered monastic life after being deeply shaken by teachings on hell and death, and soon became disillusioned with what he perceived as lax and superficial practice in the temples he encountered. This early phase was marked by doubt and spiritual crisis, which planted in him a fierce determination to seek an authentic realization that could withstand the deepest existential fears.

His first major breakthrough came in his twenties through intense engagement with koan practice, particularly the famous “Mu” koan. Immersed in this inquiry, he experienced a powerful kenshō that seemed at first to resolve his doubts. Yet this awakening did not bring final rest; it opened instead a new field of questioning, as he came to sense that his understanding was still incomplete and unstable. The very experience that might have satisfied a lesser seeker became, for him, a spur to further, more uncompromising practice.

The decisive turning point arrived when he placed himself under the stern guidance of the hermit master Shōju Rōjin (also known as Dokyō Etan). Shōju relentlessly challenged Hakuin’s initial realization, dismissing it as inadequate and subjecting him to rigorous training centered on koans such as “Mu.” Through repeated testing, criticism, and unyielding pressure, Hakuin was driven beyond attachment to his earlier insights, until a far deeper and more unshakable realization broke through. This deeper enlightenment was finally recognized by Shōju as genuine.

Even after this recognition, Hakuin did not rest on his attainment but continued to refine and stabilize his understanding through years of further meditation, koan work, and study. Over time, his realization matured into the capacity to guide others, and his teachers conferred formal Dharma transmission (inka), authorizing him to teach within the Rinzai lineage. Returning to his home temple, he assumed the role of abbot and developed a demanding training system that combined graded koan curricula, zazen, and strict moral discipline. Through this fusion of profound personal awakening, rigorous ongoing practice, and formal recognition, he came to be regarded as a great Zen master and a central figure in the revitalization of Rinzai Zen.