The Macintosh IIci will work in Japan. It has a power rating of 100v-240v
AC, with a frequency of 50-60 hertz. The Macintosh IIci is
auto-configuring, just plug it in and it works.
If you have any problems, contact:
Apple Computer
25 Mori Bldg. 23/24F
1-4-30 Roppongi, Minato-ku
Tokyo 106, Japan