十全十美 (shí quán shí měi)

十全十美 (shí quán shí měi; be perfect in every way)

In the Zhou Dynasty, a doctor’s payment was based the cure rate of his patients. If ten of his patients all recovered from their illnesses, then the doctor would get level-one payment. If, however, only nine or eight out of ten were cured, then the doctor would receive a level two payment, and so on. Later 十全十美 began to be used to describe a perfect situation.

It is similar to the English expression: the peak of perfection.