玄
ゲン, くろ, けん, はる, はるか

mysterious, occultness

JLPT1 G7 S5 F1409

The relevant bronzeware inscription form shows *slender* threads twisted together and thus linked → *darkness* (← so slender as to be barely perceptible, a situation likened to darkness) → *obscure*; *mysteriousness*; *black*.

[Full Kanji Etymology List]