石の上にも三年 (いしのうえにもさんねん): perseverance prevails; three years on a (cold) stone (will make the stone warm)

perseverance prevails; three years on a (cold) stone (will make the stone warm)

Encouragement to stay with something difficult long enough for it to pay off. Often said to someone in a hard first year of a job.

A Japanese proverb (ことわざ)