As we approach the month of October, we note that the passing of the autumnal equinox went by without mention. On September 21, day and night were of the exact same length, they were balanced, in equilibrium, harmonious. With each passing day, however, we lean a little bit more toward the dark, with the hours of daylight growing less and less and the hours of night increasing.
It is easy to mistake this for a metaphor of slipping into ignorance. However, in Zen, the moon is often a symbol for direct realization, for seeing things as they really are, and not mere reflections on a pond or in a pail of water. We look to see the moon itself, not the fingers pointing at the moon.
The distracting hours of blinding daylight intoxicate us with their overload of sensory input. These next several months provide an opportunity to move beyond the realm of the senses into directly seeing our true nature. As the autumn sky is usually very clear, this is a good time to view the moon. Zen Master Dogen wrote several chapters of the Shōbōgenzō around the time of the autumn equinox, the fifteenth day of the eighth lunar month.