Other influential garden manuals which helped to define the aesthetics of the Japanese garden are "Senzui Narabi ni Yagyo no Zu" (Illustrations for Designing Mountain, Water and Hillside Field Landscapes), written in the fifteenth century, and "Tsukiyama Teizoden" (Building Mountains and Making Gardens), from the 18th century. The tradition of Japanese gardening was historically passed down from "sensei" to apprentice. The opening words of "Illustrations for designing mountain, water and hillside field landscapes" (1466) are "If you have not received the oral transmissions, you must not make gardens" and its closing admonition is "You must never show this writing to outsiders. You must keep it secret".