Kenkyo (顕教)
Kenkyo (also pronounced Kengyo) (exoteric Buddhism) is the disclosed teaching of Buddhism. It is the antonym of Esoteric Buddhism. It is one of the Kyoso Hanjaku (evaluations of sutras) classified by Kukai, the founder of the Shingon sect, from the perspective of the superiority of Esoteric Buddhism.
Kukai distinguished Kenkyo from Esoteric Buddhism through the following:
Kenkyo
A teaching clearly disclosed by Shaka Nyorai (Buddha Shakamuni) who revealed himself to enlighten all living things.
Esoteric Buddhism
A teaching of Dainichi Nyorai (Mahavairocana), who seldom reveals himself, in the form of shinri (literally the truth) itself. A secret teaching that cannot be easily disclosed because of its profoundness.
According to Kukai's interpretation, scriptures are graded as follows:
Kenkyo scriptures
Kegon-kyo Sutra, Lotus Sutra, Hannya-kyo Sutra (except one section), Nehan-gyo Sutra, among others.
Esoteric Buddhism scriptures
Dainichi-kyo (Mahavairocana Sutra), Vajrasekhara Sutra, Rishu-kyo (Principle of Wisdom Sutra), among others.
On a related note, Saicho taught Enmitsu icchi (Agreement of Tendai Integrate Teachings and Esoteric Teachings) from the standpoint of Shishu (also pronounced Yonshu) kengaku (learning the four sects) in an attempt to subsume Buddhist scriptures centering on the Lotus Sutra, and with the aim of establishing a Tendai doctrine unique to Japan and different from the Chinese Tendai sect.