Stone gardens existed in Japan at least since the Heian period (794–1185). These early gardens were described in the first manual of Japanese gardens, "Sakuteiki" (“Records of Garden Keeping”), written at the end of the 11th century by Tachibana no Toshitsuna (1028–1094). They adapted the Chinese garden philosophy 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. The "Sakuteiki" described exactly how rocks should be placed. In one passage, he wrote: