It was reported Monday that Japanese Maritime Self-Defense Force ships and naval ships of the United States and a few other countries fired at and sank a decommissioned U.S. Navy ship during an exercise off Hawaii in July 2010.
Apparently this was an exercise for the MSDF and the navies of the other countries to practice jointly using force against a common enemy. The government's traditional position, though, is that the war-renouncing Constitution only lets Japan exercise the right to individual self-defense, thus prohibiting Self-Defense Forces from participating in military drills commonly associated with the right to collective self-defense.
It is deplorable that the MSDF appears to have violated the government's ban on taking part in a military exercise premised on the right to collective self-defense with other countries and that the Democratic Party of Japan-ruled government hid that information from the public and the Diet.