historically influenced by chinese law, the japanese legal system developed independently during the edo period through texts such as kujikata osadamegaki. since the late 19th century, the judicial system has been largely based on the civil law of europe, notably germany. in 1896, japan established a civil code based on the german bürgerliches gesetzbuch, which remains in effect with post–world war ii modifications. the constitution of japan, adopted in 1947, is the oldest unamended constitution in the world. statutory law originates in the legislature, and the constitution requires that the emperor promulgate legislation passed by the diet without giving him the power to oppose legislation.