Both parents have duty to support their children. Even when the parents divorce, both parents are obliged to share the expense of bringing up their children (Child Support, “Yoikuhi” in Japanese).
If parents cannot reach agreement about the amount of child support, the parent who has the custody of their children can go to the family court to file a petition for conciliation (“Chotei” in Japanese) to demand child support from the other parent.
Moreover, even if they have already decided the amount of child support, the amount can be changed depending on the parents’ economic situation.
At the conciliation, the petitioner and the other party will discuss with the conciliation committee, and the committee will give suggestion and advices to let the parents reach an agreement.
When the parents could not reach agreement in the mediation, trial will be started automatically. In the trial, the judge will decide about the child support, considering all circumstances.
If you have trouble regarding child support, it is suggestible to see an attorney (Bengoshi lawyer) for consultation. Attorney (Bengoshi) is the only license which can support the legal procedure about child support in Japan.