Cleansing job

WHEN the Japanese army retreated from China at the end of the second world war, it left behind thousands of shells filled with deadly chemicals. Half a century on, Japan faces the huge cost of disposing of these rusting relics of its military past. Starting on April 29th, the countries that have ratified the Chemical Weapons Convention have ten years in which to get rid of their stocks of chemicals used in warfare, to dismantle the plants for making them, and to remove any chemical weapons left behind in other countries. Japan's sole obligation is to deal with the shells left in China in 1945. That is more than enough to keep the Japanese busy.