is composed of senior bureaucrats and a minority of judges, some of whom go on to join the Supreme Court. It has the responsibility of thoroughly investigating government legislation to avoid constitutional flaws. Proponents of this view argue that this process prevents the need for the Supreme Court to frequently strike down legislation, as violations of the constitution are removed during the legislative phase. Composition The composition of the Supreme Court is defined by the 1947 Judiciary Act. The Supreme Court is composed of a Chief Justice and fourteen other Justices. These Justices are divided into three Petty Benches of five, which adjudicate most appeals. Questions of constitutional interpretation are adjudicated by the Grand Bench of all fifteen Justices, of which nine are needed for a quorum. Associate Justices of the Supreme Court are both selected and appointed by the Cabinet of Japan but the Chief Justice differs in being appointed by the Emperor of Japan. Justices are required to be over the age of forty and possess an extensive knowledge of the law. Unlike in other countries, Supreme Court judges in Japan are subject to retention elections after being appointed. In the first general election after being appointed, a judge can be dismissed if a majority votes against them, but a Supreme Court Justice has never been dismissed in this way. Although a public review is stipulated to occur every ten years after appointment, since Justices are generally appointed at age sixty or older and must retire at age seventy, there are effectively no "second reviews." Particular to the Supreme Court of Japan is the uncodified custom of having seats of the court be allocated to different legal professions: career judges, private attorneys, prosecutors, academics and bureaucrats. The numbers for each group have been subject to some variation, but overall have been remarkably stable since the court's inception. Facility The modern Supreme Court was first convened in May 1947 in the former Privy Council quarters of the Tokyo Imperial Palace. It moved to the Tokyo District Court building in September of that year. It was intended to occupy the building of the Supreme Court of Judicature, the previous highest court during the Imperial Japan era, but the building was largely destroyed in the war and had to be rebuilt. In October 1949, this reconstruction was completed and the Supreme Court of Japan would use the building for twenty-five years.