（1） Secret， occult， esoteric， mysterious， hidden， profound; teachings that are not readily understandable without a deep insight into the nature of Buddhist reality， or without a special instruction or initiation. The opposite of this is the readily apprehensible 显了teaching. （2） The teachings of Maha^vairocana Tatha^gata 大日; esoteric teaching. （3） According to Zhiyi 智顗， one of the four types of the Buddha's teaching， wherein the listener is made to think that only he is hearing the sermon and the level of understanding among those in the audience （who are unaware of each other） is different.