Japan and Korea have restrictive gun laws, but they don’t have even 1/100th the murder rates of many Sub-Saharan African or Central American countries. Most of Europe has/had restrictive gun laws, but they had low murder rates until they experienced a mass influx of African and Middle Eastern immigrants.
Or as they say, guns don’t kill people, people kill people.
Yes, culture is the driver on murder rates. Murder rates are likely the most reliable of crime statistics, but even they are suspect in many thuggish countries. China's murder rates are mostly unknown, because the Communist party is known to fudge its figures.
The murder rate in Korea is about 1.9 per 100,000. The murder rate in Japan is about .3 per 100,000.
The highest murder rates in Africa or Central America are in the 30 - 60 per 100,000.
That is more than 100 times the rate of Japan, but far from 100 times the rate of S. Korea. North Korea is said to have a much higher murder rate of 4.7 per 100,000, about the same as the United States.
North Korea makes it very difficult to obtain such data.