"Hidden Faces in the Thatched Cottage" is not only a treasure of Kang Youwei's calligraphy art, but also Kang Youwei's theoretical work on painting. Kang Youwei had a "sexual addiction to writing" since childhood. In 1889, which was the first time he wrote to the Qing emperor, he was criticized by the feudal stubborn Japanese faction. He "washed his heart and hid the secrets, but his spirit was swept away" ("Guang Yi Zhou Shuang Ke Ji Preface"), " I read the steles every day and look at thousands of kinds of gold and stone from collectors in the capital." ("Kang Nanhai's Self-Compiled Genealogy"). He is also good at calligraphy. When he is near the pond, he uses a garden pen exclusively to show off his boldness and does not avoid rudeness. His writing style is strong and bold, and he is especially good at making big and bold characters. He is as famous as Wu Changshuo and Shen Zengzhi in the late Qing Dynasty. calligrapher.