During the practical operations of National Law of Restitution, there are many insufficient aspects which need revising.

It covered fields in which case law was dominant and the effect of varying state statutes was minimal: agency, conflict of laws, contracts, judgments, property, restitution, torts, and trusts.

To analyze the offset, the assignment, the "ex tunc" adjustment, the interest calculation etc. of the restitution right of tax law by using civil rules on debt and credit for reference.