Japan's case numbers have abruptly plummeted, and no one really knows why
                                
                                
                                    (Newser) -
                                    Almost overnight, Japan has become a stunning, and somewhat mysterious, coronavirus success story. Daily new COVID-19 cases have plummeted from a mid-August peak of nearly 6,000 in Tokyo, with caseloads in the densely populated capital now routinely below 100, an 11-month low, per the  AP . The bars are packed,...