Just don't call it JAP input.
That's racist.
JIS people.
Thanks for the consideration, ripster.
I will try to demystify the Japanese IME and the JIS/ISO keyboard layout. Please bear with me as English is not my first language.
The Japanese language has three character systems
1. Kanji - this is the imported Chinese character that we have been sharing with Chinese (traditional Chinese) for about one thousand years.
Example: 英語 - pronounced as "ei-go" meaning "English"
2. Hiragana - this character system is the backbone of Japanese language and all the Kanji can be written in Hiragana. Kids or people who are trying to learn Japanese start with Hiragana.
Example: 英語 can be written as えいご,
3. Katagana - this character system is reserved for words of "foreign-origin" and Japanese language use this system to "Read" foreign words.
Example: イングリッシュ - reads like "Inn-gu-ri-shu" meaning "English"
It is because of this complicated language we need so many extra buttons to assist us "transforming" between different character systems.
Now how about the Japanese characters on the keyboard, are they necessary? Well, not really. One can type all three systems perfectly well on an ANSI keyboard using the "romaji" input system, it would just involve more keystrokes. However it is easy to learn and under this input system, one need only type out the pronunciation and then choose the right character system.
example: itsumoarigatougozaimasu (meaning: Thank you as always)
23 keystrokes plus space key for 1st level transformation to hiragana, you'd get
いつもありがとうございます
and after a few more "transformations", you'd get the "proper Japanese:"
いつも有難う御座います
but if you want to be a purist and want to type real fast in Japanese, that's when you will need to learn the KANA layout.
One would type the mapped pronunciation keys on the KANA layout resulting only 13 keystrokes and transformation keys
It's complicated, isn't it.
Most younger Japanese now use the "romaji" input system, eliminating the need to have Kana characters printed on the keyboard and some even prefer ANSI layout.
You can use the Japanese ISO layout on a US system without installing the IME system, it will behave just like another ISO keyboard. You can even use the extra keys in gaming if you want. they can be quite handy sometimes.
One last point thou', as ripster pointed out earlier, the KANA characters indeed make the keyboard looks more, er, exotic, some of my American friends use it to impress chicks.
