Po men chou chang (A collection of poetic exchanges between the Su brothers and their disciples) contains 660 poetic exchanges between Su Shi (1037−1101) and Su Zhe (1039−1112), the two famed Song brothers, and responses in verse by their students, including Huang Tingjian (1045−1105), Qin Guan (1049−1100), Chao Buzhi (1053−1110), Zhang Lei (1054−1114), Chen Shidao (1053−1102), and Li Jian (1059−1109). This copy from the National Central Library is a Song edition produced in Yuzhang. At the front is a piece by Shao Hao (jin shi in 1163), written in the first year (1190) of the Shaoxi reign of the Song, entitled Po men chou chang yin (Introduction to poetic exchanges by the Su brothers), followed by the preface (also dated 1190) by Zhang Shuchun of Yongjia, Vice Chamberlain of Ceremony, later Minister of Personnel. The avoidance of Song dynasty taboo characters is observed in the book by omitting the last stroke in each character, such as xuan, xian, jing, yin, and so forth. The imperial temple names were not avoided as taboo after Song emperor Ningzong (reigned 1195−1224). The book has a smooth and shining surface; probably no restoration has ever been done. On the flyleaf of Juan 1 is a handwritten note (dated 1907) by the book collector Yun Yuding (1862−1917), which explains the provenance and features of the copy. It reads: “This is a facsimile handwritten copy of a Song edition from Tianlu Linlang, the Qing Imperial Palace Collection. During the tumult of the Genzi year (1900), when the Eight-Nation Alliance troops sacked the capital, most of the collected items in Shiqu ting ge were destroyed by the alliance army. This book ended up in the Italian Embassy. It was acquired by writer, archaeologist, and late-Qing politician Liu E of Dantu (1857−1909). However, Liu could not keep it with him, so in the same year collector Dong Kang (Shoujin, 1867−1947) acquired it from him for a huge sum of money, and showed it to his fellow collectors. Though it was of good quality, it was not as refined as the Song print edition.” This copy has a number of seal impressions by the renowned Ming book collector Li Tingxiang (1485−1544) and by modern-era collectors Liu Shiheng (1871−1926) and Zhang Junheng (1872−1927). The seal impressions include Puyang Li Tingxiang Shuangguitang shu ku si yin (Private seal of Shuangguitang, the library of Li Tingxiang of Puyang), a rectangular seal with the characters in red; Guichi Liu Shiheng jian cang jing ji jin shi shu hua ji (Records of classical works, bronzes and stones, paintings and calligraphy in the collection of Liu Shiheng of Guichi), a square seal with the characters in red; Juqing mi ji, shi zhe bao zhi (Books owned by Juqing. Those, who recognize them, treasure them), a rectangular seal with the characters in red; Ju xue shu cang (Books of Juxuexuan Library), a square seal in white; and Qin pu shou cang (Zhang Junheng’s collection), a rectangular seal with the characters in red. Besides the facsimile copy, no other copies of the same edition are known. During the second and third years of Xuantong (1910−11) this title was included in the facsimile edition of Yuhaitang ying Song cong shu (Yuhaitang series of Song facsimiles), published by book collector Liu Shiheng. The prefaces, table of contents, and Juan 1−2 are presented here.