Karesansui (2)

The Japanese rock garden (枯山水 karesansui^?) or "dry landscape" garden, often called a zen garden, creates a miniature stylized landscape through carefully composed arrangements of rocks, water features, moss, pruned trees and bushes, and uses gravel or sand that is raked to represent ripples in water.^[1] 

Early Japanese rock gardens

Rock gardens existed in Japan at least since the Heian Period (784-1185). These early gardens were described in the first manual of Japanese gardens, Sakuteiki, or Records of Garden Keeping, written at the end of the 11th century by Tachibana no Toshitsuna (1028–1094). They were largely copied from the Chinese gardens of the Song Dynasty (960-1279), where groups of rocks symbolized Mount Penglai, the legendary mountain-island home of the Eight Immortals in Chinese mythology, known in Japanese as Horai.^[3]
  
Classic zen gardens of the Muromachi Period (1336-1573) 

Classical zen gardens were created at temples of Zen Buddhism in Kyoto, Japan during the Muromachi Period. They were intended to imitate the intimate essence of nature, not its actual appearance, and to serve an aid to meditation about the true meaning of life.^[2]

Gravel is usually used in zen gardens, rather than sand, because it is less disturbed by rain and wind.

The most famous of all zen gardens in Kyoto is Ryōan-ji, built in the late 15th century.