Meaning of little kanji in left corner

[vacchins]

Hi guys, can someone tell me what those little colored kanji on top of a big kanji mean?
thank you

[alo]

天 - Heaven
上 - Above
下 - Below

Are you using a script?

[Belthazar]

Looks like the Semantic-Phonetic Composition script to me.

[alo]

@Belthazar

Looks like the Semantic-Phonetic Composition script to me.

Ah, got it.

@vacchins Check out this link:

1000×1000 11.8 KB

I 'm using phonetic semantic script but I have no idea how it work and what it mean anyone can guide me how to read it??? Is that work for newbie like me ? or it’s only efficient for immediate and advance [15]

Basically:

天 - perfect match, the phonetic component is the reading
上 - close match, the phonetic component is one of the readings, but maybe not the main one
下 - the phonetic component is not used for the reading or it uses a different phonetic component