佛祖統紀 45.41

45.41

洛陽沙門鑒聿。深於易述韻總五篇。歐陽修為之序曰。推子母輕重之法。以定四聲。考求前儒之失。辨正五方之訛。儒之學者莫能難也。

The monk Jianyu of Luoyang, being deeply versed in the Book of Changes, composed the Yunzong (Summary of Rhymes) in five sections. Ouyang Xiu wrote a preface for it, saying, 'He deduced the rules of heavy and light for mothers and children to determine the four tones, investigated the errors of earlier scholars, and corrected the discrepancies of the five regions. Not one of the Confucian scholars could confound him.'