The Yìjīnjīng (Chinese: 易筋經; literally "Muscle/Tendon Change Classic) is a text written by Zining Daoren (literally "Zining, the Taoist") perhaps most notable as the source of the attribution of the Shaolin martial arts to Bodhidharma.

^*fter Bodhidharma faced the wall for nine years at Shaolin temple, he left behind an iron chest; when the monks opened this chest they found the two books “Xǐ Suǐ Jīng” (Marrow Washing Classic) and “Yí Jīn Jīng” within. The first book was taken by his disciple Huike, and disappeared; as for the second, “the monks selfishly coveted it, practicing the skills therein, falling into heterodox ways, and losing the correct purpose of cultivating the Real. The Shaolin monks have made some fame for themselves through their fighting skill; this is all due to having obtained this manuscript. (Lin Boyuan, Zhōngguó wǔshù shǐ 中國武術史, Wǔzhōu chūbǎnshè 五洲出版社, p. 183)

The text has been dated to 1624 CE but no copy published before 1827 remains extant.

None of the many texts on Shaolin martial arts in the intervening thousand years attribute them to Bodhidharma.

The bulk of the Yìjīnjīng is copied from "Transmission of the Lamp" texts, which consist mainly of the history and parables of Chan Buddhism.

Also notable are its forewords, one of which purports to be by the General Li Jing writing during the Tang Dynasty, the other purports to be by General Niu Gao of the Southern Song Dynasty. It is inconsistencies in these forewords that cast doubt on the veracity of the text.

The "Li Jing" of the foreword reports that Bodhidharma arrived in the Wei kingdom during Xiao Ming's "Tai He" year, but the "Tai He" era took place during the reign of Xiao Wen. "Li" also claims that he received transmission from Qiuranke, a fictional character from an eponymous Tang short story.

The "Niu Gao" of the foreword mentions the Qinzhong temple, which wasn't erected until 20 years after the date he claims to be writing. He also claims to be illiterate. Dictation could resolve the question of how an illiterate could write a foreword, but it is almost certain that a general of Niu Gao's stature was not illiterate.

Moreover, Bodhidharma, by all accounts, stressed direct personal transmission and downplayed—even denigrated—textual scholarship, yet the "Bodhidharma" of the Yíjīnjīng disappears leaving his followers books to learn from. Of interest is his ability to write in Chinese script, as most legends related to Bodhidharma state that he was either of Central Asian, Persian, or Indian origin.

During the 18th century, the scholar Ling Tingkan concluded that the author of the Yíjīnjīng must have been an "ignorant village master."

The earliest modern scholars to critically examine the legendary history of the Chinese martial arts were Tang Hao, Xu Zhedong, and Tang Fansheng, who outlines the inconsistencies of the text in his 1930 "Reference on Shaolin and Wudang." Their work was continued by Matsuda Takamoto in his 1979 "Illustrated History of Chinese Martial Arts" and Kang Gewu in his 1991 "Practical Guide to Chinese Martial Arts."

Chinese martial arts