The pronunciation of the characters is indicated by the so-called fanqie system 反切 ("reverse cuts") which came up during the period of the Southern and Northern dynasties 南北朝 (300~600) when the changing shapes of characters (from seal script to chancery script), changing pronunciation and the intensive contact with foreign languages in shape of Buddhist writings made it necessary to create a standard pronunciation. Two older books using the principle of rhymes, Li Deng's 李登 (mid-3rd cent. CE) Shenglei 聲類 and Lü Jing's 呂靜 (c. 300 CE) Yunji 韻集, from the Three Kingdoms 三國 (220-280) and the Jin period 晉 (265-420), respectively, are lost.
The Qieyun was finished in 601. The original is lost, but a manuscript fragment (Tang xie canjuan 唐寫殘卷) is preserved which was discovered in Dunhuang 敦煌 by Aurel Stein (1862-1943), as well as fragments quoted in other books. In the past decades, numerous manuscript fragments from the Tang period 唐 (618-907) came to light which makes it possible to understand the general structure of the book, even if the text is not preserved completely. Wang Guowei 王國維 (1877-1927) published some of these fragments in manuscript form (Tang xieben Qieyun canjuan 唐寫本切韻殘卷).
The Qieyun consisted of 8 juan and included 11,500 characters, arranged in 193 rhyme groups (yun 韻). 53 rhyme groups were level-tone rhymes (pingsheng 平聲), 51 falling-rising-tone rhymes (shangsheng 上聲), 56 falling-tone rhymes (qusheng 去聲), and 32 entering-tone rhymes (rusheng 入聲). The first three categories were arranged in a fixed sequence. Below the rhyme-group level, the characters were arranged in groups of homophones.
Below first character XXX of such a homophones paragraph the pronunciation is indicated by the fanqie system, and the number of homophones. The meaning of the characters is explained briefly, and many common characters (which the user should know) do not have such an explanation at all – the Qieyun thus served often only to check the correct pronunciaton of a character. For quite a few characters, an alternative pronunciation is indicated (you yin X 又音Ｘ "also pronounced X").
The oldest commentary on the Qiequn was written by Zhangsun Neyan 長孫訥言 (fl. 678), another one by Pei Wuqi 裴務齊 (c. 700).
There were some revisions of the text in which not only errors are corrected, but missing characters and definitions added. These editions are called "enlarged editions" (cengdingben 曾訂本), and include the versions or editions of Guo Zhixuan 郭知玄, Guan Liang 關亮, Xue Xun 薛珣, Zhu Shang 祝尚 and Qiu Ti 邱遞. In some of them, the characters indicating the pronunciation were "modernized" to adapt pronuncatiation to younger standards. In others, some of the rhyme groups were split into two (namely 儼 and 釅).
The greatest change in this respect was realized by the Tang period scholar Wang Renxu 王仁昫 (fl. 706) in his Kanmiu buque Qieyun 刊謬補缺切韻 "Cut Rhymes, revised and enlarged". One fragmentary copy of Wang Renxu's edition, found in Dunhuang, is preserved in the Bibliothèque nationale de France in Paris, another one, based on the Dunhuang version, is part of Liu Fu's 劉復 (1891-1934) collection Dunhuang duosuo 敦煌掇瑣. A complete edition of Wang's version, with a colophon (ba 跋) of Song Lian 宋濂 (1310-1381), was published in 1947 by the Palace Museum (Gugong Bowuguan 故宮博物館).
There are basically two revised editions of the Qieyun of superior quality, one is Wang Renxu's edition, and the other is an integral part of Chen Pengnian's 陳彭年 (961-1017) Da-Song chongxiu Guangyun 大宋重修廣韻 from the Northern Song period 北宋 (960-1126). A third edition of rather good quality is an edition with a colophon written by Xiang Yuanbian 項元汴 (1525-1590) - the so-called "colophon version" baben 跋本 or "version held by the Imperial Household" (neifu cang ben 內府藏唐寫本, based on Wang Renxu's version). All these revisions are based on the Tang-period manuscript (Tang xieben 唐寫本).
There was another book called Qieyun, compiled by the Tang period scholar Li Zhou 李舟 (740-787). The book is lost, but it is known that its arrangement of rhyme groups influenced later rhyme dictionaries.