pupil surpassing the master
A literary term derived from the Chinese proverb 青は藍より出でて藍より青し (blue comes from indigo but is bluer than indigo). Used almost exclusively in the fixed phrase 出藍の誉れ (the honor of surpassing one's teacher). Not used as a standalone noun in modern conversation.
See also: 青は藍より出でて藍より青し
He achieved the honor of surpassing his master.
The word 出藍 comes from the proverb 'blue comes from indigo but is bluer than indigo.'