Snow, moon, flower
Setsu Getsu Ka
 

Master Dogen composed a poem that goes:

In spring, a flower blooms,
In summer, a cuckoo cries,
In autumn, a beautiful moon,
And in winter, snowfall and coolness revealed.

The key word of this poem is not "flower", not "moon", not "snowfall", but it is "coolness". Dogen is pointing to cool mind, cool life.

However, snow, moon, and flower are the representatives of seasons, and with snow, Zen people say, the universe falls, with moon the universe shines, with flower the universe blooms. This is "coolness".

My teacher, Soen Roshi (1907 - 1984), wrote a haiku poem that goes:

Mountain coolness
Dharma net
Now spread East and West!

By Kogetsu Roshi und Eido Roshi