The transmission
Hakuin Ekaku (1686-1769) was the Japanese master who revived and systematized the Rinzai Zen school, giving koan practice the structured curriculum still used today.
He is the originator of the famous koan “What is the sound of one hand clapping?” and a tireless teacher who insisted that genuine awakening (kensho, “seeing one’s nature”) must be a real, transformative breakthrough, not an intellectual nicety—and that even after the first awakening, practice must continue to deepen and integrate it.
He emphasized cultivating a “great doubt” so total that it shatters the conceptual mind, after which insight erupts spontaneously. For the mind-power lineage, Hakuin represents Zen’s most refined technology of consciousness: the koan as a deliberate device to corner the rational mind until it surrenders, producing a direct, non-conceptual seeing of one’s own nature.
This engineering of insight—using a paradox to force a shift in awareness—is a structural ancestor of modern “inquiry” methods (self-inquiry, “who am I?”, and contemporary direct-pointing exercises that use questions to dissolve the sense of a separate self).
His insistence that awakening is real and must be embodied, not merely conceptual, anticipates the modern emphasis on lived realization over belief. Through D.T.
Suzuki and later teachers, Hakuin’s koan Zen became the West’s primary image of Zen practice.
What they gave
Systematized koan practice: Built the structured koan curriculum that defines modern Rinzai Zen.
- “Great doubt”: Taught using total existential doubt to shatter the conceptual mind into insight.
- Sound of one hand: Created the archetypal koan as a consciousness-shifting device.
- Embodied awakening: Insisted realization be real and integrated, not merely intellectual.
In their words
Sentient beings are primarily all Buddhas: It is like ice and water, Apart from water no ice can exist; Outside sentient beings, where do we find the Buddhas?
Not knowing how near the Truth is, People seek it far away,—what a pity! They are like him who, in the midst of water, Cries in thirst so imploringly;
Taking hold of the not-thought which lies in thoughts, In every act of theirs they hear the voice of the truth.
As the Truth eternally calm reveals itself to them, This very earth is the Lotus Land of Purity, And this body is the body of the Buddha.
For penetrating to the depths of one’s own true self-nature, and for attaining a vitality valid on all occasions, nothing can surpass meditation in the midst of activity.
At the bottom of great doubt lies great awakening. If you doubt fully, you will awaken fully.
You know the sound of two hands clapping; tell me, what is the sound of one hand?
The line they stand in
Influenced by: the Linji/Rinzai tradition; classical koan collections; Tang-dynasty Chan masters.
- Influenced: modern Rinzai Zen; D.T. Suzuki’s Western presentation of Zen; contemporary koan and inquiry-based practice.
Revelations they taught
Essential Works
- Wild Ivy (Itsumadegusa)c.1765
- Song of Zazen (Zazen Wasan)c.1750