Tokyo has seen a spike in coronavirus cases, enough of a spike that it's now passed a threshold that could require it to reimpose some quarantine measures.
Tokyo's new coronavirus cases climbed to 55 on Wednesday (June 24), according to public broadcaster NHK,
the highest levels since early May, after a cluster of infections were found at an office.
With a population of 14 million people, Tokyo has sought to keep new cases below 20 a day after Japan lifted a state of emergency on May 25.
Tokyo has said it could re-impose restrictions if the figure crept up to 50 or more.
The city's governor had warned of a "large number" on Wednesday as more positive test results followed a cluster of seven infections previously found at the office.
The governor also said that in addition to the office cases, more than 10 infections emerged from group testing in Shinjuku - an area known for its nightlife - on Wednesday.
Tokyo - like the rest of Japan - has been spared the kind of explosive outbreak seen elsewhere around the world.
But meanwhile, Japan has also become a victim of its own success as slowing new infections has led to a shortage of patients to enroll in clinical trials.