Emperor
Social commentary aside, the white king is the king that wears all white. Traditionally, this is someone better than a king. The emperor!
See the emperor, garbed all in white. There are other kings, but the emperor's white clothing shows his status above the rest.
こう, おう
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Who is the emperor? It is こういち. こういち the emperor stands over his subjects.
How did こういち become emperor?! His first decree as emperor is that everybody must learn kanji now. Note: from now on, Emperor こういち will be a recurring character for the reading mnemonic of こう.