How to save Japan from demographic catastrophe

There is a solution to prevent a demographic collapse of Japan without any upfront costs or changes in immigration. Specifically, Japan needs to restructure the future pensions of young people to make their pensions dependent on the number of their children. For people younger than 25 35 year old, Japan needs to add a 1025 increase to their future pension for each child, upto 3 children. Japan can compensate the proposed pension increase by decreasing the pension of childfree people, who harm Japan economy by selfindulging at the expense of fulfilling their moral obligations to extend their family lines.