Q: How long does it take a Japanese to get spousal visa's for work in the States?
For a US spousal visa, see http://japan.usembassy.gov/e/tvisa-main.html
Best amount of time is 3 weeks.
Worst time amount of time is 8+ months.
Average time amount of time is about 3 months.
BOTTOM LINE: Always plan ahead.
The smart idea is to apply for the "pre-entry" spousal visa, the " I-130 petition", get the pre-approval, then hold on to the pre-approval papers till the time they are actually needed: "after an immigrant petition is approved, can the foreign relative start the second step".
Also http://japan.usembassy.gov/e/visa/tvisa-7137c.html
"U.S. military personnel and American citizens who are long-term residents of Japan do not need to appear at the Embassy and are strongly encouraged to send in their I-130 petitions by mail. "
Find your exact situation and choose the proceedure here
http://japan.usembassy.gov/e/visa/tvisa-7136.html