Lower level sunken courtyard illustration

Quick answer：

A lower level sunken courtyard, also known as a sunken garden or sunken courtyard, is a garden design feature where the garden is at a lower level than the surrounding ground. This design creates a sense of privacy and intimacy. The illustration typically shows the layout of the garden, including the placement of plants, pathways, and structures like fountains or pergolas. It is often used in traditional Chinese gardens, but can be found in other architectural styles as well.