Shugai 書概 "Basics of calligraphy" is a book on calligraphy written during the late Qing period 清 (1644-1911) by Liu Xizai 劉熙載 (1813-1881), courtesy name Bojian 伯簡, style Rongzhai 融齋 or Wuyazi 寤崖子, from Xinhua 興, Jiangsu. He obtained his jinshi degree in 1884 and was provincial education intendant (tixueshi 提學使) of Guangdong. After retirement he was a teacher in the Youmen Academy 尤門書院 (see academies) in Shanghai. Among is many writings, the essay collections Gutong Shuwu liu zhong 古桐書屋六種 and Gutong Shuwu xuke san zhong 古桐書屋續刻三種 must be mentioned. His Shugai is part of Yigai 藝概, a collection of articles on art and literature. Other scholarly contributions are the phonetical studies Siyin dingqie 四音定切, Shuowen diesheng 説文疊聲 and Shuowen dieyun 説文疊韻.
The Shugai consists of 245 paragraphs that deal with a wide range of issues related to calligraphy. The language is concise and quite to the point, and thus had a great influence on later books of the field, all the more as Liu offers his own unique insights in the first place, even if he also quotes from older texts. Liu interpreted artworks as expressions of the personal character of their creators, be it their education and knowledge, their individual skills and abilities, or their mental standpoint towards the art – not to speak of the quality of their instruments, brush and ink. Liu continues usage of the old concepts of energy flow (qi 氣) and rhythm (yun 韻) which are both important factors contributing to the quality of an artwork, for instance, by producing outstanding (qi 奇) results. The most important writing styles were in his eyes the running script (xingshu 行書) and the grass script (caoshu 草書), the former expressing intention (yi 意), and the latter standards (fa 法). Following traditional concepts, Liu Xizai also assesses the artistic quality of selected artists and their works.
The text can be found in the collection of Liu's literary remains, Gutong Shuwu yishu 古桐書屋遺書, and the series Lidai shufa lunwen xuan 歷代書法論文選.