The Association of Southeast Asian Nations or ASEAN was established on 8 August 1967 in Bangkok by the five original Member Countries, namely, Indonesia, Malaysia, Philippines, Singapore, and Thailand. Brunei Darussalam joined on 8 January 1984, Vietnam on 28 July 1995, Lao PDR and Myanmar on 23 July 1997, and Cambodia on 30 April 1999. The ASEAN region has a population of about 500 million, a total area of 4.5 million square kilometers, a combined gross domestic product of almost US$ 700 billion, and a total trade of about US$ 850 billion.
The ASEAN Plus Three cooperation began in December 1997 with the convening of an informal Summit among the Leaders of ASEAN and their counterparts from East Asia, namely China, Japan and the Republic of Korea (ROK) at the sidelines of the Second ASEAN Informal Summit in Malaysia.
The ASEAN Plus Three process was institutionalised in 1999 when the Leaders issued a Joint Statement on East Asia Cooperation at their 3rd ASEAN Plus Three Summit in Manila. The ASEAN Plus Three Leaders expressed greater resolve and confidence in further strengthening and deepening East Asia cooperation at various levels and in various areas, particularly in economic and social, political, and other fields.
Since then, a number of key documents have been adopted to set the direction for ASEAN Plus Three cooperation. These include the Report of the East Asia Vision Group (EAVG) of 2001 and the Report of the East Asia Study Group (EASG) of 2002.