The Eight Principles of Yong are used by calligraphers to practice how to write the eight most common strokes in regular script, using the fact that they are all present in the character 永; yǒng; 'forever'', 'permanence'. It was believed that the frequent practice of these principles as such when beginning one's study could ensure beauty in the Chinese calligrapher's writing.

The Eight Principles are influenced by the Eastern Jin-era Seven Powers (七勢) by Lady Wei Shuo. Publications on the principles include:

• The Tang-era Praise to the Eight Principles of "Yong" (永字八法頌) by Liu Zongyuan^[1]
• The Tang-era Praise to the Eight Principles of "Yong" (永字八法頌) by Yan Zhenqing^[2]
• The Yuan-era Eight Ways to Explain "Yong" (永字八法解) by Li Puguang,^[3] which provides two-character metaphorical names

• The principles, as shown in the Vietnamese book Nhật dụng thường đàm 日用常談 (1851), with their individual strokes.
• A section in Ngũ vân lâu tăng đính tứ thể thư pháp 五雲摟增訂四體書法 (1848), explaining the concept of the Eight Principles of Yong.
• The Eight Principles of Yong depicted the calligraphy book, Tứ thể bút thức 四體筆式 (1869)

• CJK characters
• CJK strokes