Why does Neal Stephenson use the term Nipponese instead of Japanese?

Question

Is there any particular reason why Neal Stephenson consistently refers to Japan as Nippon, and the Japanese as the Nipponese? I first noticed this in the novel Cryptonomicon, again in Reamde, and finally in the Diamond Age, which I just finished.

I realize that Nippon is considered a formal name for Japan (according to the Wikipedia entry, Japan was referred to as Dai Nippon Teikoku from 1868 up to the end of World War II), but it seems odd that he would use this formal term rather than the more familiar one while he doesn't seem to do this sort of substitution for any other countries/peoples.

According to the same article, Japanese people refer to themselves as Nihonjin.

Answer 1

In the footnotes for Cryptonomicon, Stephenson highlights that...

Men with experience in Asia use the word "Nip." The Colonel’s use of "Jap" suggests that his career has been spent in the Atlantic and/or Caribbean.

Clearly he's suggesting that anyone with real-world experience of Japan (like him, for example) would refer to Japan as Nippon, especially in a futuristic world where Japan has more power and influence.

Answer 2

Actually the Japanese call our country "Nihon", "Nippon" is a very "patriotic" way of saying Japan. No one really says "Nippon" these days and most people will relate the word of "Nippon" to the second world war.

And you are correct, we call ourselves "Nihonjin" and not "Nipponjin".

Answer 3

The pronunciation of the Japanese word for Japan is Nippon. So if Japan is influential in the future, it makes sense that their own name for their country would become dominant elsewhere as well. Like most people refer to the USA as America, even though there are actually many countries in both American continents. Nippon-koku is the formal use (not Nippon). Nippon-koku means The State of Japan.