Shuichi Tsugawa Department of Economics at Hitotsubashi University   Naka 1-16-11 Kunitachiyamahiko 201 Kunitachi city, Tokyo 186-0004 Japan   ed121001@g.hit-u.ac.jp             JEL Areas: C7 : Game Theory and Bargaining Theory:General D7 : Analysis of Collective Decision-Making: General