Setting Up Branch/Office For International Company and Visa Sponsorship

Hoping to get some advice, perhaps from someone who has done something similar.

I am currently in talks with my previous employer to explore opportunities to work for them in Japan.

They do NOT have an office in Japan.

I need to have my visa sponsored and remain in Japan. I currently have a 5 year engineer visa with over 4 years remaining, obtained from my current employer.
I'm trying to work out the best (simplest/cheapest/safest) way to set up some sort of company/office so that I may work for my previous company and remain here legally with my visa.

The best solution would require minimal set up in japan, and we do not plan to have sales done through me/the registered branch/office. None of the work I would be doing would be to do WITH Japan, I would just be physically living here. (We do have sales in japan but through other partners)

I understand there is a Representative Office, Branch Office, and then the GK/KK.

I am just wondering if you are looking for somebody to offer help, but then move your serious discussion to the PM system or other means of communications?

I mean, it seems after a first read that discussing out here in public the serious business matters associated with the many questions you are asking would be mighty not-so-good.

AND, if you are going to be doing business anywhere on this planet and you are going to be using the English language to conduct that business I would very much appreciate your using language in a professional manner, such as properly using upper-case lettering, when it is called for.

I write that I would appreciate it because it seems that folks the world over are getting sloppier and sloppier with their use of language and as an old-old geezer, that is beginning to irk me more and more and to the point that I just wrote that above to you, TallNuck.

And I should correct something; any language used should be used in a professional manner. Not just English.

And I will now ask for some clarification on one point; do the two employers know of each other and how they will be intersecting in what seems to be a three-way business arrangement? You want to work with your previous employer, but remain within the legal confines of the present employer's visa arrangement that you presently have?

And if you feel it is better to answer my question using the PM system here, that's fine by me. I think I'll be around here a little longer, even though thomas .is probably more than a little pissed off at me.

Thank you for the reply,

Yes, I was hoping to get general advice to start, perhaps from someone who has done something similar before. Any further details would of course move off the forum into PM.

Long story short, I would be changing companies, leaving my current employer (which my visa is currently tied to) and joining my previous employer. This all hinges on being able to set up an appropriate office for the previous employer to be able to then sponsor my visa, as I would have to move the sponsorship to them. As they do not have any entity in Japan at the moment, they cannot sponsor my visa.