Gu's calligraphy, mostly imitating Liu Gongquan, must be big enough to make his brushwork sound. Representative works include Hua Yan Shu, Dongpo's poem on cold food, Song Fengge's poem written by himself, Liu Binke's poem on Fu Bo Temple, etc. Among them, Hua Yan Shu is vigorous and has formed its own physique, but the pen and ink are relatively moist. Although the silk book is damaged, the spirit of calligraphy has not been lost, which is his masterpiece of middle-aged calligraphy. The words of Dongpo's cold food poems are very close, but their strokes are horizontal, ups and downs, sober and straight, showing a strange and stubborn spirit in awkwardness. It seems that Dongpo's poetry style fluctuates, so he is eager to compete with him. Poems of Songfengge was written in the first year of Chongning (1 102). The Han Palace is tight, the strokes are unrestrained, and the words are tied together. Use a pen, use a pen heart. In fact, Liu Gongquan's calligraphy is used, but it is abnormal and exaggerated, which makes people feel brand-new. Poetry pays attention to thoroughly remoulding oneself, turning stone into gold and turning decay into magic. Valley calligraphy is like his poetic skills.