Gardens of Nippon have long been classified, according to the character of the ground, into two general types: tsuki-yama (artificial hills) and hira-niwa (level gardens), the vicissitudes during the past one thousand years and more having developed some special features in each. As the names signify, the former consists of hills and ponds, while the latter treats of a flat piece of ground to represent generally a valley or a moor. Needless to say that the two are not always separable: the former, if it is of a considerable size, concedes a part of it to the latter. Earlier in history, for centuries, the main garden on the south side of the house of a nobleman was invariably in the tsuki-yama style, but for the treatment of spaces between different buildings the hira-niwa style was necessarily resorted to where Nippon taste seems to have been more in evidence. Thus, the two types developed side by side until the necessity rose to choose one or the other for a limited space of ground available. Especially since cha-no-yu came into vogue in the fifteenth century, the hira-niwa has made wonderful progress, developing into a distinct type known as roji, or cha-seki garden, but to this we shall return later.
