A 5-year-old boy was reunited with his father in Germany last month under the Hague convention, the first case in which a child was returned from Japan to another country in accordance with the treaty on cross-border child custody disputes, the Foreign Ministry said on Wednesday.

The child, born to a German father and Japanese mother and who lived in Germany with his parents, was taken to Japan in June by his mother after she left her husband, according to a ministry official.

At the end of August, the father applied for help from the ministry through the German government to return the child under the treaty. After negotiations, the mother voluntarily took the boy back to Germany in mid-October, the official said.