Also a lot of the Koreans in Japan migrated before 1940, peak in 1930. So the Koreans taking up citizenship are often third generation living in Japan, after be

Also a lot of the Koreans in Japan migrated before 1940, peak in 1930. So the Koreans taking up citizenship are often third generation living in Japan, after beeing culturally fully integrated. So according to your numbers it would be fair to put the 'real foreigners' who took citizenship in the 0,1 to 0,3% range.