The Japanese family law system uses two separate, but similar provisions regarding custody and parental responsibility. (international-divorce.com)
A law - generally - is a piece of legislation passed by a state, or in common law systems, may also be the principles that are stated within decisions by courts. (law.stackexchange.com)
For that reason, statutes in civil law systems are more comprehensive, detailed, and continuously updated, covering all matters capable of being brought before a court. (law.stackexchange.com)