if you can do all, read, write and speak. then you are going to be very marketable
my japanese skill far from perfect, but enough to express my ideas and opinions and ask question with the help of body language and flow charts.
so if your japanese skill is not yet good, target those big companies that deal with international clients like NEC, Sharp, Mitsubishi, Ricoh, Epson. Most if not all their engineers can speak/understand english.
Try searching in JDV international site..