Karesansui, Sh白石, Clean

Quick answer：

Karesansui, also known as dry landscape, is a Japanese garden style that emphasizes the beauty of simplicity, often featuring raked gravel and rocks. Sh白石 refers to a type of white granite stone, commonly used in Japanese gardens for constructing steps or as a decorative element. Clean, in this context, relates to maintaining the gardens' pristine appearance by regularly raking the gravel and removing debris.