This chapter presents four case studies documenting ways in which Japan's precarious workers have mobilized in opposition to Japanese employers, and some of the effects that the workers have had in doing so. Nonregular workers face working conditions characterized by precarity, lack of bargaining power, low wages, and a rapid turnover of employment. Nevertheless, these case studies illustrate a number of important ways in which, through collective action, nonregular workers in Japan have been able to impose a number of sanctions on employers and receive a range of important concessions. This has led to changes in corporate governance, better treatment of workers, the payment of unpaid wages, and improved employment security. In some cases, solidarity among precarious workers has led to the collapse of temporary employment agencies (temp agencies), clearly demonstrating that workers' acts of refusal can generate changes in employment practices.