精益求精

to perfect sth that is already outstanding (idiom); constantly improving

essence / extract / vitality / energy / semen / sperm / mythical goblin spirit / highly perfected / elite / the pick of sth / proficient (refined ability) / extremely (fine) / selected rice (archaic)

surname Yi

benefit / profit / advantage / beneficial / to increase / to add / all the more

to seek / to look for / to request / to demand / to beseech