What is the most difficult thing to paint in Chinese painting?

Chinese painting to figure for the most difficult, followed by landscape flowers and birds, because the character is the most see modeling skills, the most difficult to convey the spirit, and figure painting is the most god of the character's eyes. Su shi in the "record of the god" in the Gu Kaizhi's "passes the god to write the picture", said: "passes the god of the difficult in the eye. Gu Hu Tou Yun: Transfiguration writing shadow, are in the A plug." Here the "A plug" is "this", "here" meaning. In Gu Kaizhi's view, "this" is the character's eyes. He drew the characters, years without eyes, once the eyes, to point out the good, so he said: the spirit of writing, is "A plug" in.