It is important to point out, however, that the low fertility rate is not exclusive to Japan. Eastern European countries like Slovakia and Poland have an even lower fertility rate, not to speak of South Korea and Taiwan. In what ways could this population decline impact Japan? The impact is already palpable if Japan and South Korea had a demographic dividend [1] post WWII. A demographic ... Lack of Immigration: Japan and South Korea do not receive immigrants like western countries do. This is partly ... The Korean government is well aware of the declining birth rate and is taking measures to combat it.