_In paintings of panoramic landscapes, mountains are placed in ranges one above the other; even in one foot's space they are deeply layered; . . . and proper order is adhered to by first arranging the venerable mountains followed by the subservient ones. It is essential that . . . forests cover the mountain. For the forests of a mountain are its clothes, the vegetation its hair, the vapor and mists its facial expressions, the scenic elements its ornaments, the waters its blood vessels, the fog and mists its expressions of mood.2 _ Two characteristics of Sung landscape paintings that were later to become important elements in the canon of Zen aesthetic theory were the use of empty space as a form of symbolism, later to be found in all of Zen art from rock gardens to the No theater, and the specific treatment of rocks and trees, elements that the Zen school would one day take as metaphors for life itself. These characteristics have been eloquently described by the Western critics Osvald Siren and Ernest Fenollosa, respectively: _We hardly need dwell on the well-known fact that the Chinese painters, and particularly those who worked in Indian ink, utilized space as a most important means of artistic expression, but it may be pointed out that their ideas of space and their methods of rendering it were far from the same as in European art. Space was not to them a cubic volume that could be geometrically constructed, it was something illimitable and incalculable which might be, to some extent, suggested by the relation of forms and tonal values but which always extended beyond every material indication and carried a suggestion of the infinite.3 The wonderful twisted trees, mighty mountain pines and cedars, loved by these early Chinese and later Japanese, which our Western superficial view first ascribed to some barbarian taste for monstrosities, really exhibit the deep Zen thinker in their great knots and scaly limbs that have wrestled with storms and frosts and earthquakes--an almost identical process through which a man's life-struggles with enemies, misfortunes, and pains have stamped themselves into the wrinkles and strong muscular planes of his fine old face. Thus nature becomes a vast and picturesque world for the profound study of character; and this fails to lead to didactic overweighting and literary conceit, as it would do with us, because character, in its two senses of human individuality and nature individuality, are seen to become one.4_