The Supreme Court ruled on Thursday in favor of a U.S.-based Japanese father seeking to reunite with his teenage son, who was taken by his estranged wife to Japan in 2016, concluding that the wife's dogged refusal to abide by an earlier court order mandating the minor's repatriation amounts to her "illegally confining" him.

The ruling is believed to be the first by the Supreme Court on cases where return orders by courts have been refused. It is likely to send a strong message regarding domestic legislation that is often slammed as impotent on cross-border child abductions, despite Japan's commitments under the Hague Convention, following mounting criticism that return orders issued by courts have been ignored.

The Supreme Court sent the case back to the Nagoya High Court.