These are the Chinese characters for “Buddha nature.” “Bu [Butsu]” is “Buddha,” and “shō [sshō]” is “nature.” In Mahayana teaching, it is said all beings have Buddha nature. But my teacher’s teacher, Sawaki Kodo Roshi said we all have “thief nature.” Buddha nature and thief nature are both a hundred percent; [we are not partly buddha and partly thief]. Depending on our activity as a practice, we manifest Buddha nature or manifest thief nature. “Thief nature” means we always want to get something and make it my own possession. That is thief nature. Even [with respect to] enlightenment; if we practice in order to gain that desirable thing called “enlightenment,” then we are manifesting thief nature. So Buddha nature is manifested when the only thing we do is just practice without expectation of gaining. So in Dogen Zenji’s teaching, just to practice (“just sit;” that is called “shikantaza”)—just to sit, without even expecting or desiring enlightenment, that is the manifestation of Buddha nature.
(Transcription thanks to Mark Bykoski)