How long to process a dependent visa?

My husband, a US citizen, is currently in Japan on a work visa for a year participating in his law firm's work exchange program with a Japanese client. He has been there for about 2 weeks now. We recently got married and I, also a US citizen, have applied for a dependent visa through his sponsored employer about 2 weeks ago. Does anyone know how long it generally takes to process and obtain a dependent visa? I understand it's a two step process where they need to obtain a certificate of eligibility before applying for the dependent visa. His sponsored employer has requested for my visa to be expedited and regularly sponsors attorney's from my husband's law firm for the work exchange program. I would like to go over to Japan in time for the Obon holiday.

Any insight would be greatly appreciated!

You can have the visa process done in Japan,,, waiting in U.S. is time wasted,,, U.S. citizen with a passport can stay in Japan visa waived for 90 days,,, ample time for your husband's employer to secure the dependent visa for you.

Thanks Sue for your response.

I was under the impression you could not obtain a dependent visa once you enter Japan and that you had to have it before entering the country. I am wondering if it is feasible to go to Japan on a tourist visa and leave and re-enter with the dependent visa once it was processed and issued.