The Meaning of the Three Barriers of Chan Buddhism

The three gates of Chan (Zen) are checkpoints for the advancement of wisdom. The first gate is the realization of tathāgatagarbha. The second gate is seeing the nature of tathāgatagarbha, that is, the Buddha-nature—being able to see, in each of the six sense objects, the functions arising from tathāgatagarbha. The third gate is the "fortified gate" (laoguan); once one passes through this gate, the great matter of birth and death is resolved, and one gains the ability to enter nirvāṇa. When Chan meditation practice is complete, one must then proceed to study the Vaipulya Yogācāra teachings.

Realization through Chan corresponds to the first fruit of the Small Vehicle. Passing the third gate corresponds to the third and fourth fruits of the Small Vehicle. Attaining the fruit of the Great Vehicle simultaneously brings the fruit of the Small Vehicle, whereas attaining the fruit of the Small Vehicle does not necessarily include the fruit of the Great Vehicle—this shows that the Great Vehicle encompasses the Small Vehicle. When an arhat sees emptiness, he sees the emptiness of the self of persons, knowing that the five aggregates and eighteen elements are empty and not the self, but he has not yet realized tathāgatagarbha. When a bodhisattva sees emptiness, he realizes that tathāgatagarbha is real, that it is the mind of emptiness (śūnyatā), while also knowing that the dharmas of the five aggregates and eighteen elements produced by tathāgatagarbha are empty. Both realize emptiness, but their content is not entirely the same.