the blue sea; blue waters
Formal or literary term for the vast blue ocean; often used in poetic or elevated contexts.
It is no more than a drop in the vast blue sea.
The poet sang of the blue sea.
青い海 is the everyday phrase for 'blue sea'; 滄海 is a single Sino-Japanese compound used in formal or poetic writing.
hidden gem; unrecognized talent
Standard kanji form; 滄 means 'blue' or 'vast water'.
Variant using 蒼, also meaning 'blue' or 'deep blue'.
Sino-Japanese compound from 滄 (blue, vast water) and 海 (sea). The exact historical derivation is uncertain, but the spelling is conventionally associated with the deep blue ocean.