KanjiJLPT N1
Emperor

Mnemonic

A blinding white light descends from the heavens and strikes the king, transforming him into an emperor. The white radiance clings to his robes like a sacred second skin, proof that the gods themselves chose this king to rule above all others as their divine sovereign.
Additional thoughts
White sits on top of King in the kanji, just as the divine white light descends from above onto the king, elevating him. Think: white = heavenly purity, king + divine blessing = Emperor.
Quick recall
A white heavenly light descends upon the king, making him the emperor chosen by the gods.

Details

The keyword for 皇 is emperor. This kanji refers specifically to an emperor in the most exalted sense, carrying connotations of supreme sovereign authority and divine rulership. In Japanese context, it is most closely associated with the Japanese imperial line, regarded as descended from the gods. It conveys a sense of majesty, sacredness, and the highest possible rank of monarchical power.
On'yomi
こう、おう