Working visa to business manager visa

I�fm currently in engineer/specialist in humanities/international services visa.
I�fm planning to change into business manager visa after establishing a company.
Currently I have 3 year visa for engineer/specialist in humanities/international services.
My question is what's the visa period given when I get a business manager visa for the first time.
Is there Preferential treatment for the previous visa and its validity period?

If you apply to change your visa status, you will be given one year visa under new status I guess. After you keep renewing every year, it can be extended maximum to 5 years. Depend on your tax payments situations, social insurance and you strong ties with Japan.

I am not aware of any situation where you would get more than one year for an initial Business Manager visa. Getting one for longer than one year depends on a lot of factors and it is not obvious, although there are some metrics that are more important than others. Also note, it is a difficult category to get.
BTW - I am on my 6th one-year period and expect my next renewal to also be just one year.