My guess is MtGox keeps a fairly low profile in Japan?
Yes. I can add my data point here; there is very, very, little knowledge of Bitcoin in Japan, even among tech-minded types.
In my case, I had held a lot of JPY which had done fairly well for me (vs for example USD) but that seems to have ended. Should have bought more BTC before Abe-kun came in.
The debt expansion / QE / printing / whatever you call it is on the news here. There was also an NHK peice a few days ago where they talked to grandmas in line to buy gold bars / coins at some dealer in Tokyo. Apparently there's that, and also people going into stocks.
So that's what's on TV. Who knows what's actually happening.
I can get from JPY physical cash to an MTGox accoount at well under 0.1% transfer fee here. Takes like an hour. I Bet if I opened a Suitomo account I could get that even lower, to maybe a flat 200 JPY fee or so. Non-anonymous bank transfer, but still, very, very easy.
So in that sense Japan is quite well set up for Bitcoin adoption.
I sort of worry that the whole reason MTGox is in Japan though is that Japanese regulators have no idea what MTGox is doing, in fact no regulator has ever even heard of it... in fact likely the bank MTGox uses probably has no idea either... and for all involved, trying to find out or ask is not in their job description. We'll see how long this situation lasts.