An investigation revealed Sunday that many records relevant to landmark civil cases in Japan since World War II no longer exist, having been disposed of by courts across the country.

The almost 140 cases scrutinized focused on issues such as nationality, freedom of expression, separation of state and religion, expropriation of land for national defense, and the constitutionality of the Self-Defense Forces. The type of documents lost are mainly hearings during the trials, not judgments.

Under Japanese regulations, documents that “should be historical records or reference data” must be kept “under special preservation.” District courts are usually supposed to preserve records for five years after a decision or a resolution of disputes is reached. Decisions are supposed to be preserved for 50 years.

However, even among the 18 constitutional civil cases where documents had been retained, special measures had only been applied in six cases and only one had been sent to the National Archives of Japan. “In the United States, it is understood (that record preservation) is necessary to protect freedom and democracy,” said Hiroshi Asako, a Waseda University professor emeritus who is an expert on judicial record preservation. “In Japan, there is a need for this to be better understood.”