before the advent of readily available pocked wifi and rental of devices at the airport, i had the 2nd edition of this.

http://www.amazon.com/gp/product/156...R240SYZD4692RR

I still keep it and mark it up with things i find on my trips to Japan.

Once you get the system, it works very very well. I never got lost once. I did have to get some help when you needed to find the exact building from an address or i ended up walking around a while to find it, but it was not too bad.

[BTW, if you want to arrange a volunteer guide for your trip in Tokyo, they can show you around for free. just contact one of the groups in Tokyo. Full list here.

http://www.jnto.go.jp/eng/arrange/tr...teerGuides.php ]