Re Mobile telephone and cruising permits

As written before...
Being an overseas visitor = Non Resident, (as in Not Having a Japanese Address) you can't  get a Mobile Voice Telephone.  Usually a friendly resident will jump-in, but listen to what sailing yacht DAGON managed! (june 2012):
As you'll need a cruising permit to cruise around in japan...YOU somehow HAVE an address!!
So with their cruising permit in the hand they were able to obtain a SoftBank Mobile phone.

Funny enough, for a Mobile DATA (only) Phone you don't need an address...and so you can get easily a SIM card.

Next, The Cruising Permit.
Sailing Yacht Anthea applied for their cruising permit, June 2012 @ Naha, Okinawa. They were told: 
"Here is your cruising permit with starting data &  place (Naha, Okinawa) and finale data & place (Nagasaki).
You can stop anywhere as long as you stay between these dates and places"
Wow,  that's Good News, but will have to see if other prefectures will do the same.

AND indeed, it doesn't work. (update June 12th)
Just  got a report from sy Anthea that the JCG in Amami Ohshima ( that is Kagoshima prefecture) gave them a hard time not having the "right" papers. So make sure you have a cruising permit with all the ports printed where you like to stop at.

Also, if you'll have to make a stop at a port that's not on the list, call 118 (so you'll need that telephone) and tell Japan Coast Guard why you like to stop.