Introduction Ancient Chinese gardens, according to the differences of ownership, function and scale, are divided into three basic types: imperial gardens, private gardens, and temple gardens 1)2). Among them, imperial gardens and private gardens, as essential space for daily activities of owners including emperors, scholar bureaucrats and literati stratum, are two existing types of Chinese gardens which stress the gist of "nature in city and living beside nature landscape" in traditional gardening culture 3). In the construction process, the garden designers emphasize the overlap between the physical space and the artistic conception, and project the interest and aesthetic appreciation of the ancient literati into the natural image of traditional poetry, literature, painting and other artistic works, and then uses the garden space as the carrier of expression. Among them, the horizontal tablets (hereafter refer to as HT) and other written form of garden elements are the main expression of the owners' interests and aesthetic standards 4). However, as for imperial gardens and private gardens, there are significant differences in location, scale, garden space structure, and the hierarchical identity of the owners of the gardens. The main expression in each HT and the corresponding characteristics between HT and garden space also reflect differently. Therefore, the comparative analysis of the spatial features of the two types of gardens from the aspect of HT is essential for further clarify and differences between the two types of gardens. Previous studies on the HT in ancient Chinese gardens were relatively adequate from the aspects of form, contents and calligraphy art 5)6)9). There are also studies on the specific function of the HT in the overall garden space and the relationship between the HT and the garden space 4)7)8). Moreover, the previous research on the correlation between HT and garden space has focused on imperial gardens and private gardens in Korea and China 10)11)12)13). There are also comparative studies between imperial garden in China and Korea 14). However, there is a lack of 扁額からみた中国・西苑皇家園林と蘇州私家園林の建築類型別の庭園空間特徴
