Guang yizhou shuangji 廣藝舟雙楫 "Extended double oars of the boat of arts" is a book on calligraphy compiled by Kang Youwei 康有爲 (1858-1927). Apart from this study, which is a kind of supplement or continuation of Bao Shichen's 包世臣 (1775-1855) Yizhou shuangji 藝舟雙楫, Kang wrote some essays on the calligraphy of stone inscriptions (beiming 碑銘) of the Northern Wei period 北魏 (386-534).
The book of 6 juan length is divided into 27 chapters. It begins with the historical development of calligraphy (ch. 1), with a focus on "venerable" inscriptions on stone slabs (2 Zun bei 尊碑), the inscriptions of which were so important that Kang appealed to collectors to purchase whatever they could (3 Gou bei 購碑). Kang then (ch. 4-6) explains the emergence of different writing styles as it becomes evident from inscriptions of the Qin 秦 (221-206 BCE) and Han 漢 (206 BCE-220 CE) periods, from the large (zhou 籀) and small seal script (zhuan 篆) to the chancery (li 隸) and the standard script (kai 楷). In a next step (ch. 7-11), the author discusses the value of stone slab inscriptions of the Northern Dynasties 北朝 (386~581) and the Sui period 隋 (581-618), and derides the traditional admiration of Tang-period 唐 (618-907) calligraphy (12 Bei Tang 卑唐). The next part (ch. 13-19) narrates the history of stone inscriptions and provides criteria to rank and assess the artistic value of individual works (ch. 17-18). Kang also gives instructions (ch. 20-23) in the right use of the brush and talks of his own experience as a calligrapher. He then (ch. 24-26) goes over to a discussion of special styles, namely sign boards at buildings (pangshu 榜書), "running script" and "grass script" (cao-xing 行草), and "script used for official purpose" (ganluti 干祿體). The last chapter (27 Lunshu jueju 論書絕句) is a kind of poetic conclusion about the theory of calligraphy.
Kang Youwei follows the steps of Bao Shichen in trying to bring an end to the conventional "study of model calligraphies" (tiexue 帖學) and to replace it by the study of stone inscriptions (beixue 碑學). The title of the book, however, is not quite appropriate because Kang only served one "oar" (ji 楫) of the arts, namely calligraphy, and does not discuss painting, which would the "second oar". The book is therefore also known with the name Shujing 書鏡 "Mirror of calligraphy".
Kang Youwei's book was printed in 1891 (Wanmucaotaong keben 萬木草堂刊本). It is included in the series Wanyou wenku 萬有文庫, Yilin mingzhu congkan 藝林名著叢刊, Kang Nanhai yishu 康南海遺書 and Sibu zonglu yishu bian 四部總錄藝術編. A modern, annotated edition was published in 1981 by the Shanghai Shuhua Chubanshe 上海書畫出版社.