The Supreme Court on Wednesday ruled that it is constitutional to place restraints on court judges' freedom of expression.

The top court thus dismissed an immediate challenge filed by an assistant judge of the Sendai District Court who had been admonished for a remark he made during a public rally protesting a law related to organized crime.

"Placing certain limits on freedom of expression for trial judges is permitted within reasonable and necessary bounds," the top court said after voting in favor of the admonishment.