There are three types of Ch’an kung-an that often bewilder Buddhologists; namely, (1)the contradictory, (2)the inexpressible, and (3)mixture of the two. D. T. Suzuki and the scholars influenced by him, for example, E. Fromm, think that these three types of kung-an imply the truth realized by Ch’an masters, the truth which goes beyond daily language and logic. However, as the author points out, there are two traditions in Ch’an School: (1)the “Buddha-nature” tradition based on the Laṅkāvatāra Sūtra, and (2)the prajna tradition based on the Diamond Sūtra. Suzuki and Formm’s interpretation only emphasizes the first tradition and ignores the second one. According to the second tradition, the contradiction and inexpressibility of kung-an may seem to indicate the truth of non-existence-śūnyatā, not necessarily indicating the truly existing “Buddha-nature”.