In this paper, my aim is to address the imagery and symbolism behind expressions in the works of the founder of the Japanese Soto school, the Zen master Dogen ?? (1200—1253), with an emphasis on the image of the moon, tsuki ?. Dogen often makes poetic references to the natural world and its symbolism, among his most favourite are, for instance, the four seasons, flowers, rain, wind, and breeze, mountains, streams, and valleys, as well as animals such as horses, donkeys, snakes, and dragons. I would like to illustrate Dogen’s usage of a most common expression of the moon, an oft-portrayed Zen symbol for wisdom, insight, and enlightenment. Dogen himself frequently reaches for [the image of] the moon in his writings, the Sino-Japanese Shobogenzo as well as the kanbun-style Eihei Koroku, and even in his both waka and kanshi poems. Given the occurrence of the word tsuki in these various types of writings as doctrinal, philosophical, and poetic reference, I would like to investigate the numerous instances where Dogen mentions this word, and thereby to illustrate the multidimensionalism of Dogen’s use of language and imagery.