If a court has changed a trial date in abuse of its powers, the persons concerned in the case may request the taking of judicial administrative measures pursuant to the Rules or the Instructions of the Supreme Court.
裁判所がその権限を濫用して公判期日を変更したときは、訴訟関係人は、最高裁判所の規則又は訓令の定めるところにより、司法行政監督上の措置を求めることができる。
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Supreme Court
最高裁判所
The highest court, and the court of last resort on whether any law, order, regulation or official act conforms to the Constitution (Article 76, paragraph (1), and Article 81). That power is what makes the Constitution enforceable: there is no penalty attached to breaching it, and instead a conflicting rule is held to have no legal force (Article 98, paragraph (1)). Its judges are reviewed by the people at the first general election after appointment, and again after ten further years (Article 79, paragraph (2)).
Written by AI using Constitution, Arts. 76, 79, 81, 98 and Wikipedia: Supreme Court of Japan as a reference.