Just to add to this, one thing you can learn from the iPhone's success in Japan is "don't let Japanese exceptionalism blind you to good and innovative solutions that people will pay you a lot of money for". The Japanese love to tell you how unique they are and how different everything is here. It isn't hard to get the typical Japanese salaryman halfway up his own ass in Nihonjinron bullshit after a few beers. In that, they are like nearly every other people on Earth, but for some reason they seem the most convincing. It's probably being on an island and having a tough language, and some other stuff.
Anyway, a "keen student" of Japan would likely have told you the iPhone would fail here (no 1seg? Ha!), and that an invoicing service for Japanese companies, built by foreigners, was an outrageously stupid idea. But the Japanese market is no more impenetrable than the American market, or the British market, or the Indian market, nor any more difficult to learn and understand (though you still have to do that, of course).
Anyway, a "keen student" of Japan would likely have told you the iPhone would fail here (no 1seg? Ha!), and that an invoicing service for Japanese companies, built by foreigners, was an outrageously stupid idea. But the Japanese market is no more impenetrable than the American market, or the British market, or the Indian market, nor any more difficult to learn and understand (though you still have to do that, of course).