Shihua 詩話 is a term for texts of literary criticism specialized on poems, with a focus on shi style poetry 詩. Criticism focused on ci 詞-style poems or songs is called cihua 詞話.
Poetry criticism is quite old and can already be found in the Han period 漢 (206 BCE-220 CE) story collection Xijing zaji 西京雜記, where Sima Xiangru's 司馬相如 (c. 179-117 BCE) theories about rhapsodies or prose-poetry (fu 賦) is quoted and contrasted with Yang Xiong's 揚雄 (53 BCE-18 CE) opinions.
The chapters Wenxue 文學 and Paidiao 排調 in the Liu-Song period 劉宋 (420-479) story collection Shishuo xinyu 世說新語 quotes a few sentences of Xie An's 謝安 (320-385) critique of the Classic Shijing 詩經 "Book of Songs", Cao Pi's 曹丕 (187-226) order to his brother Cao Zhi 曹植 (192-232) to write rhapsodies and poems, Ruan Fu's 阮孚 (c. 278-c. 326) praise of the poetry of Guo Pu 郭璞 (276-324), and Yuan Yang's 袁羊 (XXX) rating of the poems of Liu Hui 劉恢 (dates unknown).
In the official dynastic history Nanqishu 南齊書 a chapter on literary critique is included (Wenxue zhuanlun 文學傳論) that speaks about the poems of Wang Can 王粲 (177-217), Cao Zhi and Bao Zhao 鮑照 (414-466). The Western Wei period 西魏 (535-556) book Yuanshi jiaxun 顏氏家訓 by Yan Zhitui 顏之推 (531-591) includes two chapters, Quanxue 勉學 and Wenzhang 文章, in which poems are discussed and rated.
The earliest book that it fully decidacted to the criticism of poems is Zhong Rong's 鍾嶸 (468-518) Shipin 詩品 from the Liang period 梁 (502-557). It is therefore the first in He Wenhuan's 何文煥 (dates unknown) collection Lidai shihua 歷代詩話 from the Qing period 清 (1644-1911). Yet strictly speaking, the Shipin does not conform with the mature genre of shihua with theoretical discussions, but only a classification of individual authors and their oeuvre.
During the Tang period 唐 (618-907) shi-style poems were flourishing, and accordingly, many authors also wrote about poems. Du Fu 杜甫 (712-770) wrote the Xi wei liu jueju 戲為六絕句 and the text Outi 偶題, in which the basics of a theory of poetry are developed. Similar germs can be found in the writings of Li Bai 李白 (Li Taibo 李太白, 701-762), Han Yu 韓愈 (768-824) and Bai Juyi 白居易 (772-846). They developed the instruments of shishi 詩式 "styles of poems" and shige 詩格 "framework for poems".
The proper shihua genre emerged during the Song period 宋 (960-1279), with Ouyang Xiu's 歐陽修 (1007-1072) Liuyi shihua 六一詩話 as a forerunner of about 140 Song period poetry theories, as Guo Shaoyu 郭紹虞 (1893-1984) says in his Song shihua kao 宋詩話考. Of these, 42 texts or fragments have survived. In his preface Ouyang Xiu says that his intention was not to write a comprehensive and coherent theory of poetry, but to collect various information about poems an poets and to compile these in the form of a biji "brush note" style 筆記 essay. Sima Guang's 司馬光 (1019-1086) Wengong xu shihua 溫公續詩話 is written in the same style.
It was only during the Southern Song period 南宋 (1127-1279) that authors began systematically to criticize and investigate poems and their rules. Xu Yi 許顗 (dates unknown) says in his Yan Zhou shihua 彥周詩話 that the task of poetry criticism was to discriminate verse standards (bian ju fa 辨句法), to differentiate old and new styles (bei gu jin 備古今), to analyze success and merit (ji sheng de 紀盛德), to note down unorthodox occurrences (lu yi shi 錄異事), and to correct errors (zheng e wu 正訛誤).
The theoretical level of shihua texts so gradually increased and found its perfection in books like Zhang Jie's 張戒 (dates unknown) Suihantang shihua 歲寒堂詩話, Jiang Kui's 姜夔 (1155-1209) Baishi daoren shihua 白石道人詩說 or Yan Yu's 嚴羽 (1191-1241) Canglang shihua 滄浪詩話. The latter analysed the poetry of the so-called Jiangxi School 江西詩派 in a very systematical way. He found out that their poems were based on three fundaments, namely words and characters (wenzi 文字), talent and education (caixue 才學), and discursiveness (yilun 議論). Yan Yu developed the theories of the potential of poems to present "distinguished stuff (or talent?)" (biecai 別材), "distinguished interest" (biequ 別趣) and to have the ability "to arouse interest" (xingqu 興趣) and to incite "a wonderful effect" (miaowu 妙悟), and can thus be seen as the best theoretician of shi poetry during the Song period.
Among Yuan period 元 (1279-1368) writers the most important shihua texts were written by Yuan Haowen 元好問 (1190-1257); author of Lunshi jujue 論詩絕句) and Wang Ruoxu 王若虛 (1174-1243; Hunan shihua 滹南詩話).
The most important Ming period 明 (1368-1644) books on the theory of poetry are Li Dongyang's 李東陽 (1447-1516) Huailutang shihua 懷麓堂詩話, Xie Zhen's 謝榛 (1495-1575) Siming shihua 四溟詩話, Wang Shizhen's 王世貞 (1526-1590) Yiyuan zhiyan 藝苑卮言, Wang Shimao's 王世懋 (1536-1588) Yipu jieyu 藝圃擷餘 and Hu Yinglin's 胡應麟 (1551-1602) Shisou 詩藪.
Interestingly enough, this genre of shihua matured at a time when shi-style poems got more and more out of date, in favour to ci-style poems. It was therefore often criticized by Ming and Qing period scholars, especially by Yuan Mei 袁枚 (1716-1797), who said in his Suiyuan shihua 隨園詩話 that Song time shihua comments were too short and not very constructive, and often over-exaggerated the real accomplishments of certain authors, by "pointing at iron to make gold out of it" (dian tie cheng jin 點鐵成金), "taking away the body and changing the bones" (duo tai huan gu 奪胎換骨), or speaking of shi poems with the arguments of Zen texts. In spite of all these criticisms, Yuan Mei was himself an very productive poet and collector of shihua critiques from the Song period. He supported Weng Fanggang 翁方綱 (1733-1818) and his idea that a poem has to express personal feelings and emotions.
The philosopher Wang Fuzhi 王夫之 (1619-1692) was another important writer on shi-syle poems. In his book Jiangzhai shihua 薑齋詩話 he speaks of the mutual influence of emotion (qing 情) and scene (jing 景) and explains that these factors were important to find their expression in a poem, by substantiating emotions in objects and the landscape. If the intention (yi 意) of a poem was expressed in the right way, its power (shi 勢) was strong enough to "express ten thousand miles with a few feet" (zhichi xie wanly 咫尺寫萬里).
In his book Yuanshi 原詩, Ye Xie 葉燮 (1627-1703) develops a coherent theoretical system for writing poems. He also talks of the task of poems to express reality and contemporary matters and changes. Following strict guidelines for composition, a poet would have to make use of talent (cai 才),courage (dan 膽), knowledge (shi 識) and force (li 力) to perfect his work.
Wang Shizhen's 王士禛 (1634-1711) Daijingtang shihua 帶經堂詩話 speaks of the divinity of rhymes (shenyun 神韻), but is less strong in theory, like Zhao Yi's 趙翼 (1727-1814) Oubei shihua 甌北詩話 and Pan Deyu's 潘德輿 (1785-1839) Yangyizhai shihua 養一齋詩話.
In the late Qing and the early Republican period, scholars continued writings poetry criticisms, like Lin Changyi 林昌彝 (born 1803; Sheyinglou shihua 射鷹樓詩話) and Liang Qichao 梁啟超 (1873-1929; Yinbingshi shihua 飲冰室詩話). Both include political concepts in their theories of poetry.
Under the influence of the genre of shi style poetry criticism, similar types of criticisms developed for the ci-style poetry (cihua) and the qu -style arias (quhua 曲話). Li Yu 李漁 (1610-1680), for instance, has written the Li Liweng quhua 李笠翁曲話, Zhu Zhouyi 況周頤 (1895-1926) the Huifeng cihua 蕙風詞話, Chen Tingzhuo 陳廷焯 (1853-1892) the Baoyuzhai cihua 白雨齋詞話, and the Republican scholar Wang Guowei 王國維 (1877-1927) the book Renjian cihua 人間詞話. Li Yu's book is very important for the study of Yuan period qu arias. Similar texts were written for other types of poetry of prose literature, like Liu Xizai's 劉熙載 (1813-1881) Yigai 藝概 that speaks about the theory of a lot of literary genres.
Most poetry criticisms did not reach the scholarly level to create a coherent theory, but poems are often rated individually, with only a few words that only very briefly express a general, and often very personal, impression of a poem or a writer's oeuvre.