Japanese sunken garden in reality

Quick answer：

A Japanese sunken garden, also known as a kare-sansui garden, is a traditional Japanese garden style that features a flat, sunken space with carefully arranged rocks, gravel, and often a small pond. These gardens are designed to evoke the natural scenery of mountains and seas using minimal elements, emphasizing the concept of simplicity and natural beauty. Sunken gardens are often found in Japanese tea houses, temples, and residential properties.