The pressure is increasing on Tokyo to right a 28-year-old wrong and sign the statutes in the 1980 Hague Convention that deal with child abduction. Japan is the only Group of Seven nation not to have ratified the legislation, which requires a parent accused of abducting their child to return him or her to their country of habitual residence.
Yet even if Japan signs the document, it will be a bitter-sweet achievement for thousands of mothers and fathers who have been kept apart from their children during some of the most important years of their lives. And campaigners believe that even if Tokyo does sign, the legislation may be ignored - the track record of Japanese courts is not good on such an issue.
'The Japanese constitution guarantees the husband and wife equal rights in family matters and the Japanese have signed international treaties, such as the UN Convention on the Rights of the Child, which guarantee children regular direct access to both parents,' says Walter Benda, joint founder of the US-based Children's Rights Council (CRC) - which advocates that 'the best parent is both parents'.
The reality, Mr Benda says, is 'the Japanese courts thumb their noses at these legal obligations'.
Brian Thomas, 62, who also helped to found the CRC, moved to Japan from South Wales in 1988, two years after meeting his wife, Mikako. Their son, Graham Hajime, was born in January 1990, but Mr Thomas has not been permitted to see him since April 1993, when the marriage ended. He carries his son's photo with him at all times.
'Japan is still living in the feudal age and children are seen here as little more than chattels. And the authorities here have absolutely no idea of the psychological impact that it is having on thousands of children,' says Mr Thomas. 'My own mother has gone blind now, so she will never be able to see her grandson.'