Venus, morning star, place name
皖 centers on the bright morning star Venus, and by extension is used in place names. The meanings are linked by the idea of a shining, prominent celestial body.
皖 combines 白 (white/bright) with 完, which likely contributes the sound. The character is associated with the bright morning star Venus.
The left side 白 (white) suggests brightness, and the right side 完 (complete) can be thought of as the star being fully visible. Picture the complete white light of Venus shining in the morning sky.
For カン, imagine a can of white paint spilling over the complete star: can -> カン, and the bright Venus is covered in white.
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