Keyword
blue
Info
FrequencyTop 400-500
Type
Kyōiku (1st grade) 
?
KankenLevel 10
Heisig1654
Readings
あお
(60%)
せい
(34%)
さお
(2%)
Composed of
king with a hat
moon
Mnemonic

If a king with a hat would live on the moon, he would certainly appear blue due to all of the blue light reflected off Earth.

Used in kanji (9 in total)
emotion
spirit (of life)
quiet
clear up
Used in vocabulary (379 in total)
blue; azure; green; pale; gray; unripe
blue; azure; green; green light (traffic); black (horse coat color); blue 5-point card; immature
youth; young man
Examples (200 in total)
That girl's eyes are blue.
That blue one is also mine.
This building is blue.