Sushi may no longer be an exotic treat in many countries, but the fare served by supermarkets and fast food outlets often leaves Japanese chefs aghast. Fed up with foreigners failing to honour its cuisine, Japan has set out to protect it with a set of standards for overseas cooks.The programme will try to guarantee high-quality food at Japanese restaurants around the world by giving chefs training in Japan that will lead to a gold, silver or bronze status.The popularity of Japanese food is soaring in Britain yet, while a number of Michelin-starred establishments in London showcase the cuisine at its best, all too often the food served up on conveyor belts and supermarkets shelves is a weak imitation of the original fare.Yuki Gomi, a chef and cookery teacher who runs Yuki's Kitchen in London, found herself facing an "unappetising" supermarket-bought platter of sushi at a party."There was no flavour and the seaweed was soggy instead of crisp and dry, the rice was cold and hard," she said.Akemi Yokoyama, a London-based Japanese chef and washoku teacher, said: "Sushi has to be prepared fresh. The problem with the supermarket sushi is shelf life."With the world's highest concentration of Michelin-starred restaurants, Japan takes its food seriously - in particular washoku, or traditional cuisine.Washoku has edicts on everything, from the angle of a chef's hand as it moulds sushi rice, to foliage adornment - all part of a quest for harmony and balance.Japanese officials hope the new certification system will remedy mistakes commonly made by overseas chefs, which typically range from mishandling raw fish and low hygiene standards, to overlooking the ceremonial way in which the food should be presented. ..