This document discusses the development of regional economic cooperation groups in East Asia, including ASEAN Plus Three established in 1997, and the East Asia Summit (EAS) established in 2005. It explores the relationship between these groups and their roles in working towards an eventual East Asia economic community. While ASEAN Plus Three was initially seen as the lead in community building, over time the EAS gained prominence in this role, though the groups were seen as complementary with ASEAN at the core.