I have this book 「図解でわかる 文字コードのすべて」 which lists many of the Unicode and JIS symbols that one can type. I noticed the section of enclosed alphanumerics (囲み文字). Not all kanji are included in 囲み文字 which leads me to believe that some have special meanings.
㊑ probably stands for 株式会社
However, I have no clue what ㊯ would indicate or be used for.
Some of them are obvious, yet others are not. Is there a resource that exists for how these 囲み文字 are used along with the context and meaning? Also, how is it that certain characters are chosen to be included in 囲み文字 and others not?