Hey BE
One of our guys brought his wife over and obtained her resident card based on his employment... Being she was a spouse sponsored resident she could only work "part time"... Not sure of the hour limit either 20-30 hours a week... She too was looking more for something to do rather than to bank any real coin... That being said in the Sendai area part time work is somewhat available, especially conversational English... IMO think there should be no issue depending where you hang your hat in Japan... Best of luck...
Kam-pie, JCD