work as a freelancer on a dependant visa

I would like to start this by saying that this is a hypothetical situation, however, it accurately represents my future... I have a work visa and I have a job ready to go when I get to japan, but my wife wI'll be coming too. She does not have a bachelors degree, onlyou a trade school certificate from a school of massage, so she has a dependant visa. What are her options for what? From what I understand she cannot work a full time job, but could she work part time for a massage buisness? Could she work as a freelancer where she operates without a buisness as a masuse? If she can freelance, does she have to limit her hours to the equivalent of a part time job?

Thank you for any help you can offer.

First she has to obtain permission to work.

http://www.immi-moj.go.jp/english/tetuduki/zairyuu/shikakugai.html

i have been living in japan for 3 years . and i know many people(especially from asia) on dependent and student visa work more than 28 hours a week . they cannot work more than 28 hours a week in same company but they work in other companies as a part timer . recently there's a gossip that the government will know if u work in 2 places after my number system has been applied . but i have been working more than 28 hours a week for 3 years and paying my tax . i work 28 hours each for different companies .