Issues in relation to which referendums are mandatory at the national level

Constitution of Japan (May 3, 1947; not amended since)
Article 79(1) The Supreme Court shall consist of a Chief Judge and such number of judges as may be determined by law; all such judges excepting the Chief Judge shall be appointed by the Cabinet.
(2) The appointment of the judges of the Supreme Court shall be reviewed by the people at the first general election of members of the House of Representatives following their appointment, and shall be reviewed again at the first general election of members of the House of Representatives after a lapse of ten (10) years, and inthe same manner thereafter.
(3)In cases mentioned in the foregoing paragraph, when the majority of the voters favors the dismissal of a judge, he shall be dismissed.
(4) Matters pertaining to review shall be prescribed by law.
(5) The judges of the Supreme Court shall be retired upon the attainment of the age as fixed by law.
(6) All such judges shall receive, at regular stated intervals, adequate compensation which shall not be decreased during their terms of office.

Article 96(1)  Amendments to this Constitution shall be initiated by the Diet, through a concurring vote of two-thirds or more of all the members of each House and shall thereupon be submitted to the people for ratification, which shall require the affirmative vote of a majority of all votes cast thereon, at a special referendum or at such election as the Diet shall specify.
(2) Amendments when so ratified shall immediately be promulgated by the Emperor in the name of the people, as an integral part of this Constitution.