As 2018 Pyeongchang Winter Olympics triggered the momentum of improvement in inter-Korean relationships, Seoul Metropolitan Government (SMG) set out to promote ten projects in three areas in earnest which were identified in “Comprehensive Plans for a City-to-City Partnership between Seoul and Pyongyang” announced in November 2016. As part of their efforts, SMG expanded its administrative capacity, promoted inter-Korean exchange and cooperation and set out to revise relevant laws and system. 
As from 2020, SMG’s inter-Korean exchange and cooperation has mainly focused on education on peace and reunification and support for domestic events. Among the three components of the plan, city infrastructure and economic cooperation are yet to be implemented, and socio-cultural interaction has just reached the level of the early 2000s. 
The failure to expand inter-Korean exchange and cooperation, despite the organizational reform and amendments to relevant laws such as Acts on development of inter-Korean relationship and Acts on inter-Korean exchange and cooperation, is attributable to external factors. That is, the aggravation of the international political landscape represented by the breakdown of the 2nd US-North Korea Summit impeded the implementation of the plan. Specifically, the intensifying US-China conflict has rendered the Korean peninsula problem adversarial or non-negotiable. Furthermore, external driving forces of the projects was lost as the relationships between Korea and major Northeast Asian countries like China and Japan deteriorated. Most critically, the scope and level of the potential projects were restricted due to international community’s sanction against North Korea.
Considering that the changes in international relations could negatively affect implementation of inter-Korean exchange and cooperation projects, SMG should conduct city diplomacy for “peace building”. As one of the six agendas of city diplomacy, peace building has been promoted since the end of the Cold War. Local governments have worked to prevent international conflicts in advance and mediate disputes, and settle peace after conflicts, serving roles of lobbyists, peace-makers and peace-builders. Those three roles are interconnected but the purpose of specific activities can differ according to objective and period.
Taking into consideration the above-mentioned facts, SMG should conduct the city diplomacy for peace building based on the following three strategies in order to prevent potential conflicts between the two Koreas and settle down peace on the Korean peninsula. First, multilateralism strategy. SMG should carry out multilateral diplomacy centered on international organizations for peace building. Peace-building, in particular, should be set as a key agenda of the international organization cooperation team and the activities of international organizations centered on Mayor for Peace should be steadily expanded. Second, institutionalization strategy. SMG should establish international multi-layered human networks through operating “Seoul Club” of international experts of Korean issues in connection with “Seoul Peace Initiative Consortium”, establishing “Northeast Asia Southeast Asia Capital Mayors Meeting” and fostering complementary cooperative relationship. Third, policy strategy focusing on public diplomacy for peace and security. Under this strategy, public diplomacy of local council members with solidarity and persuasion as its core values, and exchange programs and education on peace and security for foreign nationals should be prioritized.