In the classical history of calligraphic aesthetics, the Song Dynasty is an important turning point. Su Dung-po蘇東坡 is the most important person representing a new development of the calligraphic art. First, he thinks the essential character of this art is to express one's emotion. From the calligrapher's point of view, calligraphy is a kind of entertainment, a kind of game, and a way of entertaining oneself only. From the point of view of the emotional constitutive outside, however, the subject that is doing the writing is the calligrapher's mind. The influence of the constitutive outside provokes the mind, and appraisers sense the calligrapher's mood when looking at his works. Second, Su believes that calligraphy is the realization of life, for it combines spirit, breath, bone, flesh, and blood, and thus is able to present a complete image of life: it shows the calligrapher's personal character. Third, Su invents a new art to write, calling this "mind-writing"以意為書. Everything should begin from the heart. One writes with a new mind, attained through an enlightened heart. The calligrapher should attempt to incorporate the merits of all the schools of this art. Fourth, Su advocates the aesthetics of spiritual efficacy: one should attain a high spiritual level without losing his personal character, but a call from Nature is also desirable--lonesome, loose,simple, and distant蕭散簡遠 forming a special style of "gentle outside but firm inside" 外柔內剛. Fifth, form is not critical; at times aberrance must be recommendable. He thus develops the aesthetics of emotional disfigurement, proposing that true ugliness, even extreme sensibility, can also attain beauty. He further suggests that under different circumstances versatility can also achieve beauty. Beauty should not have a fixed form. To attain the original beauty for a body and an age of a thing, the artistic form should first be destroyed and then rebuilt--the most difficult thing to do for an artist.