Neither Korea nor Japan instituted government mandated total lock downs.
They did have some government restrictions, but not as much as many areas in the United States, did.
Korea did use widespread testing, contact tracing, and treatments.
The citizenry of those countries bow, rather than shake hands, already commonly wear masks, because of the widespread air pollutions that blows in from China, and because they have had pandemics before, more regularly, historically, compared to Western nations.
And the citizenry of those countries are much more likely to follow suggestions from authority figures.
It is also noteworthy, that those countries revere the elderly, culturally, and it is extremely unlikely that that the general public would consider it appropriate to take a view of, “this disease only kills old people therefore it is not my concern.”
On the other hand, there are also massive downsides to cultures that are overly authority figure driven, and Japan and Korea remain contenders for the most racist countries on the planet, have some fairly horrific rape cultures, and resultantly have some of the highest suicide rates in the world.
In fact, Japan’s suicide rate equals the U.S. murder and suicide rate combined, and South Korea’s suicide rate is much higher than Japan’s.
So, every culture has advantages and disadvantages.