Chōsui (Ch‘ang-shui Tzu-hsüan)[6.36] once asked Yekaku (Hui-chiao), of Mount Rōya (Lang-yeh), who lived in the first half of the eleventh century, “How is it that the Originally Pure has all of a sudden come to produce mountains and rivers and the great earth?” The question is taken from the _Śūrangama-sūtra_ in which Purna asks of the Buddha how the Absolute came to evolve this phenomenal world. For this is a great philosophical problem that has perplexed the greatest minds of all ages. So far all the interpretations making up the history of thought have proved unsatisfactory in one way or another. Chōsui also being a student of philosophy in a way has now come to his teacher to be enlightened on the subject. But the teacher’s answer was no answer as we understand it, for he merely repeated the question, “How is it that the Originally Pure has all of a sudden come to produce mountains and rivers and the great earth?” Translated into English, this dialogue loses much of its zest. Let me write it down in Japanese-Chinese: Chōsui asked, “_Shō-jō hon-nen un-ga kos-sho sen-ga dai-ji_,” and the master echoed, “_Shō-jō hon-nen un-ga kos-sho sen-ga dai-ji_.” This was not, however, enough. Later, in the thirteenth century another great Zen master, Kido (Hsü-t‘ang), commented on this in a still more mystifying manner.[6.37] His sermon one day ran in this wise: “When Chōsui asked Yekaku, ‘_Shō-jō hon-nen un-ga kos-sho sen-ga dai-ji_,’ the question was echoed back to the questioner himself, and it is said that the spiritual eye of the disciple was then opened. I now want to ask you how this could have happened. Were not the question and the answer exactly the same? What reason did Chōsui find in this? Let me comment on it.” Whereupon he struck his chair with the hossu, and said, “_Shō-jō hon-nen un-ga kos-sho sen-ga dai-ji_.” His comment complicates the matter instead of simplifying it. This has ever been a great question of philosophy—this question of unity and multiplicity, of mind and matter, of thought and reality. Zen, being neither idealism nor realism, proposes its own way of solution as is illustrated in the case of the Originally Pure. The following one solves the problem also in its own way. A monk asked Chōsa Keishin,[6.38] “How do we, transforming (_chuan_) mountains and rivers and the earth, reduce them into the Self?” Replied the master, “How do we, transforming the Self, produce mountains and rivers and the earth?” The monk confessed ignorance, whereupon said the master: “In this city south of the Lake, people are thriving well,— Cheap rice and plentiful fuel and prospering neighbourhood.” Tōsu Daido (T‘ou-tzu Tai-t‘ung),[6.39] of the T‘ang dynasty, who died in the year 914, answered “The Buddha,” when he was questioned, “What is the Buddha?” He said “Tao” when the question was, “What is Tao?” He answered “the Dharma” to the question, “What is the Dharma?”