一 = one
葉 = leaf
知 = to know
秋 = autumn
This phrase is about understanding the essence, changes, or decline of things from noticing slight signs or phenomena.
It refers to realising the arrival of autumn by observing a single leaf fall.
一葉知秋 (ichi-yō-chi-shū) “from just one leaf one can know that autumn has come”
Calligraphy by Vicky 