NHK reports with the figure
As mentioned yesterday, it is hard to get a read on the situation in Tokyo because testing procedures are unclear right now. Yesterday, Tokyo reported just 13 new coronavirus cases and on Sunday it reported 68 new cases.
The 78 cases reported today will exceed the Sunday figure and will mark the biggest daily increase in confirmed cases in Tokyo, bringing the total tally to 521 cases.
It certainly looks like it is going to be a matter of time before the numbers here blow up over the next few days/weeks.