Concerns over a rice shortage are growing in Japan, with empty shelves becoming noticeable in supermarkets and stores, against the backdrop of rising demand. Some consumers are trying to stockpile rice after the weather agency earlier this month issued its first-ever advisory warning of the increased risk of a megaquake along the Nankai Trough that stretches from central to southwestern Japan in the Pacific. But Japan is currently in a transitional period as new rice is being released into the market. The Ministry of Agriculture, Forestry and Fisheries has called on consumers to remain calm, a…