This paper compiles a database on the rules of origin (ROOs) of the ASEAN plus 1 FTAs - namely ASEAN Trade in Goods Agreement, ASEAN-Korea FTA, ASEAN-China FTA, ASEAN-Japan Comprehensive Economic Partnership, ASEAN-Australia-New Zealand FTA. For further insights, database compilation is also done for the bilateral FTAs forged by Japan with individual ASEAN countries and India. Multiple FTAs could create a complex web of rules. Using the database, this paper assesses the various ROO regimes of these FTAs, particularly with respect to their degree of commonality and relative restrictiveness. A methodology for measurement is formulated and restrictiveness indices are computed. The paper then suggests recommendations for ROO reforms within the context of trade facilitation and deepening East Asian regional integration. The paper also suggests further methodologies for analysis, especially where the database from the ERIA FTA mapping project could be useful.