It is just like English sayings and phrases, there are Japanese sayings and phrases as well. It is called [kotowaza ことわざ].

Today’s kotowaza

縁の下の力持ち　En no shita no chikara mochi

En no shita – under the porch/in background.

En – engawa.

An engawa or en is an edging strip of non-tatami-matted flooring in Japanese architecture, usually wood or bamboo

Engawa

Chikara – a power

He is an unsung hero

Its origin

A stone under a porch supports a pillar even if it is out of sight.

Its meaning

Working behind a scene for somebody. Or a person who is working behind a scene.

arigato