Closed sunken courtyard effect

Quick answer：

A sunken courtyard, also known as an enclosed courtyard, is a traditional architectural feature in which a courtyard is surrounded by buildings or walls, creating a private and secluded space within a larger urban environment. The enclosed nature of the sunken courtyard provides a sense of security and seclusion, and often includes lush greenery and water features. This design element is particularly prevalent in Asian architecture, such as in Japanese teahouses and Chinese gardens.