Formal regional trade agreements had been unknown to countries in East Asia until it was first introduced around 20 years ago, when ASEAN country members decided to form the ASEAN Free Trade Area part of the region started to be involved in the beginning of the new  millennium. In the meantime, countries in the region almost simultaneously have been forming bilateral preferential trade agreements  among themselves, particularly between ASEAN member countries with their counterparts in the North East. For example, ASEAN has  established formal regional agreements with other three important economies in the region, namely with China, an FTA that has been fully  implemented in 2010, ASEAN-Japan Korea.