Owners of Japan's ubiquitous convenience stores are facing a business model-threatening crisis as they grapple with the nation's demographic and labor challenges."I love working under the Seven-Eleven logo, and there is no doubt Japanese society needs convenience stores. But, honestly, headquarters has not kept pace with changes in society," said Atsushi Nara, who for 37 years has owned Seven-Eleven stores in Ibaraki Prefecture, east of Tokyo.As the 58-year-old Nara says, convenience stores, all 58,000 of them nationwide, have increasingly become a part of the Japanese social fabric since t…READ FULL ARTICLE