Xinxin Ma Professor   Hosei University Tokyo, Tokyo 1940298 Japan   xxma@hosei.ac.jp   https://kenkyu-web.hosei.ac.jp/Profiles/112/0011125/profile.html           JEL Areas: J3 : Wages, Compensation, and Labor Costs: General J5 : Labor-Management Relations, Trade Unions, and Collective Bargaining: General