Japanese law knows a principle of changed circumstances, jijō henkō no gensoku, under which a contract can be adjusted after an unforeseen change. It is treated as an exception.
In 1997, the Supreme Court ruled on a golf course whose slopes had collapsed. For the principle to apply, the court said, the change must be one the parties could not foresee and could not be blamed for. A golf course operator could not normally claim that a slope collapse was unforeseeable, and the court refused to apply the principle.