Tianjin sunken courtyard diagram

Quick answer：

A sunken courtyard, also known as an underground courtyard, is a traditional Chinese architectural feature where the courtyard is situated below the level of the surrounding buildings. It is often used in ancient Chinese cities like Tianjin to enhance privacy and provide a peaceful retreat. These courtyards are characterized by their enclosed space, which can include gardens, pavilions, and pools, creating a serene atmosphere. The diagram of a Tianjin sunken courtyard would showcase the layout and design of such a space, highlighting its cultural significance and architectural details.