Yan and Liu refer to Yan Zhenqing and Liu Gongquan, famous calligraphers in the Tang Dynasty. Their fonts are called Yan Ti and Liu Ti. Yan is vigorous and powerful, and Liu Tigao is graceful and restrained. Words like Yan and Liu are vigorous and powerful. It is also used to praise other people's calligraphy works. Also known as "Six Valley Yanjin" and "Playing Ancient Yanjin".
From Fan Zhongyan's "Bachelor of Sacrificing Stones" in Song Dynasty: "Man Qing's pen, Yan Gu." Synonym: Yan Gu Liu Jin. Usage of idioms: as object and attribute; Calligraphy. Example: Surprise at the Second Moment Volume II: This book is full of bones and muscles, and there is nothing against it.
Yan Zhenqing's regular script, which embodies a prosperous style, is called "Yan Ti" by later generations. When people talk about Yan Shu, they often point out that its most obvious characteristics are "swallow-tailed silkworm head" and "horizontal light and vertical weight", which gives people the feeling of penetrating the back of the paper, produces the artistic effect of brushwork, and gives people the artistic characteristics of heavy feeling and relief beauty.
Liu Gongquan's regular script, which is as famous as Yan Zhenqing, has Ou Yangxun's brushwork, and the strokes between the lines are closely interspersed, making it particularly broad, delicate and energetic, angular, different from Yan Zhenqing's vigorous and broad, particularly heroic, and its calligraphy is called "Liu Ti" by later generations.