Tokyo's mobile phone network is being used to monitor the whereabouts of children.
Parents whose children carry a special mobile phone can connect to the mobile phone company's "location informing service centre" and receive by fax a map showing where the child is at any given time.
At present the full Imadoko (where are you?) service, which tracks and records the phone's location during the day, is available only in Tokyo through the Personal Handyphone System from the telecomunications company NTT.
The new service is made possible because of the hundreds of mobile phone base stations located in every Japanese city.
Fears of violating basic humans rights have been raised in some quarters, but parents and teachers in Japan are used to exercising much more control over children than their counterparts in the UK. Rules regarding school uniforms are so constraining, for example, that a group of children are now protesting against the erosion of their basic human rights to the United Nations in Geneva.