How do specific characters get included in 囲み文字 and what are the meanings they convey?

Question

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.

For example:

㊑ 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?

Answer 1

囲み文字 are derived from Edo period corporate logos called 表号 which were one of the standard ways of naming or identifying a shop (屋号). You may see in the countryside some companies identify themselves with logos that look like hats or carpenter's squares. There is a good survey of traditional logos from one town here:

http://www.kokuhei.com/sa-ken/hyogo.htm

As you can see there are three main varieties: yama (山, ∧), kane (矩, ┐) and maru (丸、○). There are some other ones on that page too but you won't see them so often today. Many current businesses in Japan derive their names from these 屋号, for example Yamasa soy sauce ∧+サ, and Marui fashion outlets which are today styled "OIOI" but would have been ㋑ at some point in the distant past.

The maru variety of 屋号 became the present 囲み文字 simply through familiar use by corporations and people who had seen such symbols around town. Wikipedia has a list of commonly used kanji abbreviations and most of them are associated with business use. So, for example, ㊯ stands for a contract manufacturer.

Answer 2

In short, they are frequently used in business.

You're question is similar to asking, why is the "$" symbol included in the ascii character, but not other units like "°"? The answer is the same: because it is used frequently in business.

Business use dominates the direction of the development of computers.