The total number of human beings living on the earth is increasing. Japanese society, however, is the exact opposite. I offer four perspectives to help resolve this social vulnerability. The first is the village of Aogashima, which has the smallest population in Japan. The solution to the vulnerability in this case would be to deploy a defender of the isolated island while ensuring the legitimacy of its sustainability over the medium to long term. It would be good to design an evidence-based social system, taking into account issues related to territories, airspace and EEZ, etc. The second is Kyoto City, which has experienced the greatest population decline. In this case, while ensuring the legitimacy of medium- to long-term change, it is best to leave attempts at modern urbanization to the surrounding areas and maintain the ancient town of Gojo as it has been since ancient times. Third is the town of Tomioka, which has been affected by the nuclear power plant accident, and where many people are still living in the neighborhood or in other prefectures (including foreign countries) without changing their residency with the support of the system (Act on Special Measures for Evacuees of the Accidental Nuclear Power Plants, etc.), even after more than 10 years. There is also the issue of nuclear damage compensation disputes. Regardless of unknown or known risks, it would be good to establish a method of multi-step consensus building based on the right to self-determination in accordance with the precautionary principle. 　The last case is a comparison of Japan and Russia. I plotted the long-term trends of the society, using demographic statistics as an indicator of the national momentum, and SNS statistics as an indicator of the national wealth. Japan experienced three stages of rightward social growth based on 1955. After the Corona disaster, it is unclear whether a period of the leftward expansion will materialize. Expectations of innovation will lead the way and stimulate competition, which will be compounded by expectations of sustainability in the future as people seek to legitimize the change. Another trend in society has been to seek the role and function of integrated knowledge based on the accumulation of specialized knowledge. In order to avoid the trap of fragility, the emergence of comprehensive knowledge that dissolves the barriers of the information divide is required. On the other hand, after the collapse of the Soviet Union, the Russian Federation experienced a period of leftward expansion in which economic productivity rose under a declining population. Although it became a society with a growing population for a period of time, it was unable to demonstrate its superiority in international economic competition and experienced fluctuations similar to those seen during the period of irresolution in Japan. A regime change of aggression cannot be justified. To mitigate the turbulence of growth and development, it is advisable to add sustainability to the transformation and ensure socioeconomic risk diversification.