The Wenhai 文海 "Word Ocean" is a Chinese character dictionary from the Tangut empire of Western Xia 西夏 (1038-1227). The author is not known. The book was excavated in the ruins of Ejin Banner in Inner Mongolia, the ancient town of Heishui 黑水城 (Kara-Khoto). The fragments of the butterfly-bound book contain three parts, the level tone rhymes (pingsheng 平聲), falling-raising tone rhymes (shangsheng 上聲), and miscellanea (zalei 雜類). More than 3,000 characters are preserved on 109 pages. The name of the book and the chapter is indicated in Tangut characters. Each page is divided into seven columns, the explanation of the characters is written in small script in double columns. The pingsheng section has 97 homophones under which the characters are listed according to the initial consonant and the head (or middle) vowel. Homophones are included in one paragraph and separated from each other by a circle. The section of the shangsheng rhymes, which should have included 88 rhymes, is only partially preserved. The section "Miscellanea" is a supplement to the two other rhyme groups. Each entry is analysed in three parts, first the graphical composition of the character, secondly the meaning, and thirdly the pronunciation, indicated with the fanqie system 反切.
Source: Shi Jinbo 史金波 (1992). "Wenhai 文海", in: Zhongguo da baike quanshu 中國大百科全書, Zhongguo lishi 中國歷史, vol. 3, p. 1216. Beijing/Shanghai: Zhongguo da baike quanshu chubanshe.