Credit cards could not be used at convenience stores and other merchants across Japan for hours on Thursday following a system outage that also affected some transportation companies' credit card-linked electronic money apps.Major credit card issuer Mitsubishi UFJ Nicos Co. said the trouble began around 8 a.m. when card payments could not be processed at some merchants, while Sumitomo Mitsui Card Co. reported a similar problem.The card companies said the trouble was caused by an outage in an international credit card brand's network connecting merchants with card issuers. Sources familiar w…READ FULL ARTICLE