Japan's notoriously harsh prisons are hoping to make things easier for captives and captors alike with the introduction of uniforms incorporating RFID tags in one new building and the debut of colour-coordinated futons and clothes in others.

The Japanese government has selected nine companies, including security provider Secom, to build a hi-tech prison in Yamaguchi prefecture where guards will be able to keep track of inmates through the tagged clothing they will be required to wear.

In place of iron bars will be reinforced glass so confident are the RFID designers that prisoners will be easy to keep an eye on. No one has yet asked what the prison will do in the event of a mass nude escape attempt. The prison is expected to open in April 2007.

Meanwhile, The Justice Ministry said it would provide those doing time with colour-coordinated futons and clothes, because it had found that the colours of the present apparel clash, which tends to make prisoners aggressive, or at least nervous.

Experts have advised the government that the clashing orange and green striped bedcovers that prisons have been using for more than half a century could make prisoners nervous and aggressive, Kyodo news agency said.

The colour psychologists recommended bedding in warm colours such as brown for a good night's sleep and uniforms in mint green and pale blue.

By Michael Fitzpatrick.