Since Japan belatedly joined the Hague Convention a year ago, the Foreign Ministry has hailed the pact as instrumental in reducing cross-border child abductions involving failed marriages, but there are still several issues that need improvement, parents say.

The ministry, which oversees matters related to the 1980 treaty, said it has received 25 requests for help from parents seeking the return of children who were taken to Japan in the past 12 months.

That's much better than its tally between 2012 and 2013, when there were 81 cases of children taken from the United States, 39 each from Britain and Canada, and 34 from France.