ASEAN is not a nation, actually it is an acronym for the Association of Southeast Asian Nations.
It is an organization of ten countries. In August of 1967 five nations: Thailand, Singapore, Malaysia, Indonesia and the Phillipines formed the group to promote peace, cooperation and economic advancement and protection by working together.
An emblem was designed to represent the association. Eventually five other countries joined the association. They were: Burma in July of 1997, Cambodia in 1999, Laos also in 1997, Brunei Darussalam in 1984 and Vietnam in 1995.
In November 1993 a flag was adopted. It has a blue base with the ASEAN emblem in the center.
The symbol is a red circle with a thin white rim and then a blue rim. In the center is a bundle of ten stalks tied together which was meant to symbolize the ten countries of the group.
The colors also have meanings. All we will say about the colors at this time is that they were chosen to have at least one color from the national flag of each member nation. This was so that no one nation can feel superior to the others.
The association also is part of ASEAN plus 3 which is the present numbers cooperating with the People’s Republic of China, South Korea and Japan.
Then there is the East Asia Summit which is the ASEAM plus 3 cooperation with the nations of Australia India and New Zealand.
There is a regional forum which is an informal multilateral among 27 nations. The list includes the members of the East Asia Summit and Bangladesh, Canada, the European Union, Mongolia, Russia, North Korea, the U.S. and Pakistan. Coincidentally the ASEAN flag has at least one color from most of these countries also.