wisdom of age; sagacity from experience
A set phrase emphasizing that long life brings insight and good judgment. Often used in the proverb 亀の甲より年の功.
With the wisdom of age, he calmly solved even difficult problems.
There is a proverb: 'The wisdom of age is better than the shell of a tortoise.'
A compound of 年 (year, age) and 功 (achievement, merit), literally 'the merit of years.' The exact origin is uncertain, but it reflects the traditional value placed on experience.