This paper briefly examines the potential of the trilateral cooperation among the influential countries in East Asia, Japan, China and Korea, while China has proposed an initiative of “community with a shared future for mankind.”In the international community today, not only conventional security strives but also unconventional issues such as terrorism, communicable deseases, environment/natural disaster, financial crises, immigration/refugees, energy, are surfacing. Such global issues cannot be dealt with a single country, and they require multiple and various actors like international or regional institutions, Track II channels to counter. And today’s world needs an enhancement of global governance with a diverse range of actors.Having been rapidly developed since 1990s, China today has stronger commitment internationally as a key actor of forming a way of global governance - initiating “One Belt One Road,” and establishment of the Asian Infrastructure Investment Bank are the example. China also help the existing international institutions strengthened by assisting the United Nations’ Peace Keeping Operations, and participation in the World Trade Organization. Their “community with a shared future for mankind” has been heard practically circa 2015 and ever since, after “destined community for neigh borers” (“Community with a Shared Future for Periphery”) in 2013, and “Destined Community for Asia” (“A Community with a Shared Future for Asia”) and “China-EU destined community” (“Community with a Shared Future for China-EU”) in 2014. This initiative aims to reform the current international order and to promote a new type of power politics. The Belt and Road Initiative is a practical policy to implement it.In addition to China’s new initiative, it is critically important for the better global governance and building of regional order in Northeast Asia as well as in East Asia, that three countries sit in Northeast Asia - Japan, China and Korea - to deepen the cooperation. The tripartite framework began as a breakfast meeting in 1999, on the sideline of the 3rd ASEAN Plus Three (APT) Summit Meeting. Since the three countries sit together for the first time then, Japan-China-Korea Summit has been organized annually at the occasion of APT Summit, and it’s been held independently since 2008. Henceforth, this year celebrates its 20th anniversary. In the Joint Statement of the 7th Japan-China-Korea Trilateral Summit, held in Tokyo last May, stated that the trilateral cooperation will be sought through a new concept named “Trilateral+X.” This concept was further developed at the Trilateral Foreign Minister’s Meeting in August this year, and the “Concept Paper on ‘Trilateral+X’ Cooperation” was adopted. The Paper touches upon the possibility of cooperation, especially in the area of economy and poverty reduction, with the three and other contry/ies and fields, based on the win-win principle.What is essential for “pursuing the ‘Trilateral+X’ modality” is in economy and trade fields. The trade relations of the three countries are highly complementary to each other, so deepening of the economic ties via Free Trade Agreement, including the Trilateral FTA, and conclusion of Regional Comprehensive Economic Partnership (RCEP) in particular, are critically important. Given the size of the market, realization of RCEP will lead to the integration of rules on FTA, new fields such as intellectual property rights and e-commerce among member states, as well as help develop further the production network and supply-chain in East Asia.At the same time, it would be worthy for the three countries to consider China and Korea’s possible participation in Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTTP). The CPTTP will cover Asia-Pacific with a wide ranged, 21st century rules - on intellectual property rights, e-commerce, dripline on state owned enterprise, the environment, etc. - and make a huge, free and fair market. The FTAAP will be much realizable if China and Korea join CPTTP.Meanwhile, the coordination on regional initiatives in East Asia - Free and Open Indo-Pacific (FOIP) by Japan, Belt and Road Initiative (BRI) by China, and New Southern Policy by Korea - shall be coordinated. Japan has expressed its interest in taking part in BRI on conditions like transparency and fair procurement, etc. FOIP has 3 pillars of its focus: 1. rule of law, freedom of navigation, promotion and installment of free trade; 2. pursuit in economic prosperity (connectivity, strengthening economic ties through EPA/FTA or investment agreement); and 3. peace and stability (capacity building in maritime law enforcement, humanitarian assistance and disaster rescue, etc.). These overlap with what China has been pursuing in BRI, therefore FOIP and BRI in fact are collab rateable. Together with the New Southern Policy, the coordination of the three countries has a big potential to enhance the regional cooperation, especially in economic and trade, in a wide ranged area of East Asia to Africa, thereby contributing, if actualized, to the stability and prosperity of the international community.In reality, however, the trilateral cooperation has been faced with some hurdles. The most valuable function of the cooperation, the summit meeting has been postponed some times due to political issues such as of history or territory dispute, revealing its vulnerability. One of the idea to help overcome such condition may be to find a shared goal, in another words, a common dream. What helped Germany and France reconcile the most after the World War II, though many factors were there, was the shared dream of the European integration. In Northeast Asia, therefore, strengthening of the ties based on the existing initiatives of “Community with a Shared Future for Mankind” or “East Asia Community” can be possible.