‘This is not a

They call it X Day a major earthquake striking the heart of the worlds most populous city in the most calamitous event since the second world war. Can hi-tech solutions save Tokyo? Every day, at 5pm, the gentle melody of the childrens song Yuyake Koyake chimes across the Minato area of Tokyo from a loudspeaker one of hundreds dotted across schools and parks throughout this megacity of 37 million people. The daily jingle does more than signify the arrival of evening. It is a test for the system that is designed to save Tokyoites from what would be one of the worst natural disasters in recorded human history: an earthquake striking the centre of the most populous city on Earth. …