The Essence of the Three Gates in Zen

The Three Barriers of Zen are thresholds for the advancement of wisdom. Passing the first barrier involves realizing Tathagatagarbha. Passing the second barrier entails seeing the nature of Tathagarbha, which is Buddha-nature, and recognizing the functions arising from Tathagatagarbha within all six dusts. The third barrier is the impenetrable barrier; transcending this barrier resolves the great matter of birth and death, granting the capacity to enter Nirvana. After completing Zen meditation in the Zen tradition, one must then study the expansive Mahayana teachings, specifically the Yogacara.

Realization in Zen is equivalent to the first fruition (Srotapanna) in the Hinayana tradition. The third barrier corresponds to the third or fourth fruition (Anagami or Arhat) in Hinayana. Attaining Mahayana fruition simultaneously includes Hinayana fruition, whereas achieving Hinayana fruition does not necessarily entail Mahayana fruition, indicating that Mahayana encompasses Hinayana. When Arhats see emptiness, they perceive the emptiness of the self, knowing that the five aggregates and eighteen elements are empty and not the true self, yet they have not realized Tathagatagarbha. When Bodhisattvas see emptiness, they realize that Tathagatagarbha is true reality—the mind of emptiness—while simultaneously knowing that the five aggregates and eighteen elements produced by Tathagatagarbha are empty. Both realize emptiness, but the content of their realization is not entirely identical.