ASEAN Plus Three (APT) is a forum that functions as a coordinator of cooperation between the Association of Southeast Asian Nations and the three East Asia nations of China, Japan, and South Korea. Government leaders, ministers, and senior officials from the 10 members of the ASEAN and the three Northeast Asian states consult on an increasing range of issues. The APT is the latest development of East Asian regional cooperation. In the past, proposals, such as ROK’s call for an Asian Common Market in 1970 and Japan’s 1988 suggestion for an Asian Network, have been made to bring closer regional cooperation.
The first leaders' meetings were held in 1996 and 1997 to deal with Asia–Europe Meeting issues, and China and Japan each wanted regular summit meetings with ASEAN members afterwards. The group's significance and importance was strengthened by the Asian Financial Crisis. In response to the crisis, ASEAN closely cooperated with China, Japan, and ROK. Since the implementation of the Joint Statement on East Asia Cooperation in 1999 at the Manila Summit, APT finance ministers have been holding periodic consultations.
ASEAN Plus Three, in establishing the Chiang Mai Initiative, has been credited as forming the basis for financial stability in Asia, the lack of such stability having contributed to the Asian Financial Crisis. The Asian Currency Unit (ACU) is a proposed weighted index of currencies for ASEAN+3. The ACU was inspired by the now defunct European Currency Unit, replaced by the Euro. The Asian Currency Unit's purpose is to help stabilise the region's financial markets. The ACU as it is proposed is a currency basket and not a real currency, i.e., a weighted index of East Asian currencies that will function as a benchmark for regional currency movements.
The Asian Development Bank is currently reviewing different options concerning the technical aspects related to the ACU calculation, including the nature of the basket, the choice of fixed weights vs. fixed units, the selection of currencies to be included in the basket, the choice of weights, the criteria for their periodical revision, and other aspects as well. The Asian Development Bank was to announce the details of the ACU in March 2006 or later. However external pressures delayed this announcement although the concept was still being studied in detail. A panel discussion in February 2007 cited technical and political obstacles as having prevented the project from advancing. The unit, limited to ASEAN+3, was said to be still moving forward by mid-July 2007.
Since the process began in 1997, ASEAN Plus Three (APT) cooperation has broadened and deepened to also focus on subjects other than finance too in the discussion such as the areas of food and energy security, financial cooperation, trade facilitation, disaster management, people-to-people contacts, narrowing the development gap, rural development and poverty alleviation, human trafficking, labour movement, communicable diseases, environment and sustainable development, and transnational crime, including counter-terrorism. APT cooperation in the area of political and security cooperation has been deepened by regular dialogue and exchange of views through existing APT mechanisms, such as the APT Summit, APT Foreign Ministers’ Meeting, APT Senior Officials’ Meeting (SOM) and as well as through track 1.5 and track two dialogue, including East Asia Forum and Network of East Asia Think-tanks.In combating transnational crime in the region, the APT Work Plan on Cooperation in Combating Transnational Crime was adopted in 2006.
With the aim to further strengthening APT cooperation, East Asia Vision Group (EAVG) II was established by the Leaders of APT at the 13th APT Summit on 29 October 2010 in Ha Noi to stock-take, review and identify the future direction of APT cooperation.