Sony has a plethora of labels that can leech you into the scene in Japan.
I'll have to start my vent though...bare with me.
If you are aiming to be anything worth anything in Japan, DO NOT shoot for a label in Japan. If you are just starting out in music, aim low, and realistically. Get a name for yourself and your band in your area. Find yourself a promoter, or do it yourself. Get yourself an agent *or if you know how to, do it yourself*. Get good gigs and get momentum.
When you get *assuming you havent already* your demo together, aim for at LEAST 500 copies. Print them professionally, and include a packet of info and bios on the members in your band, and be sure to include photos. Start looking around for the most apt labels in your area or near, who are searching for new talent. If you find one, send them a bit of merchandise. A pen of your band, a button, something to whet their whistle. And build up from that. Develope a repoire with an employee; work your way into the label from the inside. Then when you get yourself rooted rather well, then offer them a spot to one of your gigs. Put on the best show you can, THEN offer them a demo. Work from that.
When that is settled, if anyone is considering contracting you, get yourself a good lawyer, to organize a contract that clearly dictates overseas publication. Use the label the best you can, form a ground base from it, THEN start your search for labels overseas. Make sure you negotiate your contract as open ended as you can, in case you find a label in the country to jump ship to; you dont want to breach contracts and get sued now...
Oh, some more things.
The most important thing when approaching a label is to manipulate them; they must want you. Not you want them, they must want you.