The aim of this study is obtain the character of the rock garden of the Botanical Gardens attached to Tokyo Imperial University College of Science (Koishikawa Botanical Gardens). In 1906, Koishikawa Botanical Gardens plan of re-development with beautifully landscaped like a park was decided by Matsumura director. The rock garden shaped like Kew Gardens was almost completed in 1915. The landscape gardening of the rock garden was gradually pushed forward afterwards, and, in 1922, the slope with Kuroboku and spray device on the 2,800 square meters site was made by Nakai gardening chief and Ihara engineer. The rock garden with the slope on both sides of the pathway and 400 kinds of alpine plants was almost completed and was designated as the special observation facilities as well as the greenhouse in 1923.
