What Is the Dharma Realm? Where Do All Buddhas Attain Buddhahood?

Question: What is the dharmadhātu (realm of dharmas)? Where did all the Buddhas attain buddhahood?

Answer: The dharmadhātu is divided into the supramundane dharmadhātu and the mundane dharmadhātu. The mundane dharmadhātu is divided into the eighteen realms, the ten dharmadhātus, and the three realms of existence. The eighteen realms are the realms of sentient beings' six faculties, six sense objects, and six consciousnesses; the ten dharmadhātus are the dharmadhātus of the four sages and six ordinary beings. "Realm" (dhātu) means function, boundary, and differentiation of seeds—that is, a dividing line. Different realms have different functions and roles: the functions of the six faculties differ from the functions of the six sense objects, and differ from the functions of the six consciousnesses. The sentient beings of the six destinies each have their own boundaries, and the four kinds of sages each have their own boundaries; the ten dharmadhātus each have their own boundaries. The three realms are the desire realm, the form realm, and the formless realm; they also have boundaries, and can also be called dharmadhātus, for the three realms likewise each have their own boundary distinctions.

The supramundane dharmadhātu is called the one true dharmadhātu, which is the tathāgatagarbha of suchness. He does not belong to the three realms of existence, is not within the three realms, and has no characteristics of the three realms of existence, yet He is also not outside the three realms of existence. All dharmas of the three realms of existence, as well as the Buddha-lands of the Buddhas of the ten directions, the worlds of the lotus treasury, and the oceans of worlds, all exist within the one true dharmadhātu, and none of them goes beyond the mind of suchness. When sentient beings cultivate to the stage of wondrous enlightenment, before attaining buddhahood, they must await their turn in the inner court of Tuṣita, waiting for the conditions to ripen, then descend to be born in the human world and accomplish the eightfold manifestation of attaining the Way. When the faculties and dispositions of the sentient beings in the human world have ripened, the time for the wondrous-enlightenment bodhisattva to attain the Way has also arrived, and he must descend to the human world and accomplish the eightfold manifestation of attaining the Way. Therefore, all the Buddhas come to the human world to achieve the fruition of buddhahood.