This report summarizes the points of the two flexibility measures, GHGs emissions trading and joint implementation, focusing on former instrument, adopted in the Kyoto Protocol, aiming at identifying the issues for designing how the regime works efficiently and what points should be settled. Proposals are also mentioned especially focusing on the
emissions trading based on the author ’s current opinion. This is the second version and therefore on developing stage of inviting comments and opinions related to this issue. Redistribution and citation with this version number are also welcome.