Japan had been under-testing and under-reporting to save their face -- or the Olympics. As recent as last week, their health official confessed they had a testing capacity for only 200 per day in Tokyo. Japan's case number and death started skyrocketing since the Olympics postponement on March 24 and nobody thinks it's just a coincidence.
Also note Japan has a large elderly population, or about 32+K, who die unnoticed in solitude every year.
Japan was certainly trying to save the Olympics but when it became clear nobody would attend, numbers "skyrocketed" the same way US numbers did, ie. we started actually testing people and confirming what everyone else already knew, that this thing spread like wildfire.
Testing isn't even useful at this point, we should operate under the assumption everyone has or will have it, and just treat those who are having complications. You don't need to get tested to know you have a cold, just deal with it.
Sure, which is to say, Japan intentionally deceived the world -- they under-tested and under-reported their case numbers to project a false perception of safety and control before the Olympics.
We didn't even have FDA approved test kits until last month, I imagine that similar agencies exist in Japan which required government intervention to expedite the process. I know you want to believe they had nefarious intentions but bureaucracy and incompetence are often the culprit when it comes to government.
In the US it wasn't just a matter of getting tests made, but getting all the various states and private testing centers connected so the federal government could aggregate the data. Smaller countries or those with socialized/public healthcare had an easier time at this because their systems were already unified. Tiny countries like South Korea trying to talk down the US for not getting tests out as fast is them is humorous. California alone has greater landmass and 80% of SK's population.
Besides that, Japan is still doing very well despite their population density meeting/exceeding many major hotspots. And the US is likely out of the woods, we should definitely be back to normal next month.
Also note Japan has a large elderly population, or about 32+K, who die unnoticed in solitude every year.