Japanese salarymen get an income tax waiver for having dependents, and also pay a subsidised fee for social insurances for dependents. The dependents will also pay their own social insurance if they earn more than this limit. Now that the limit has changed, more part time workers will pay social insurance and have smaller take-home income.

The Abe administration says that the rule will encourage women to work more. I think they will work less, because they can't work really long hours due to lack of childcare facilities, and they will be taxed if they work as long as they usually did. The real objective here is to boost the pension and health insurance funds.