In 2006, the Japanese law of nonprofits underwent a major reform. Notably, the reform involved a shift in the governance mechanism from external governmental oversight to a structure that emphasizes internal fiduciary governance. As the Japanese law in this area has historically been marked by various strands of fiduciary rules derived from different sources, the event presents a valuable case study on how the shift to a fiduciary governance approach can impact the operation of those entities that are subject to the reform. This chapter will begin with a historical account of the evolution of Japanese nonprofit law that involves complex interactions among the indigenous nonprofit tradition, the civil law influence, American fiduciary principles, and the English-style charity commission. After discussing the major components of the 2006 reform against the backdrop of major events that created the reform momentum, this chapter will use available empirical evidence to critically examine the reform’s achievements and consider any remaining issues that pose ongoing challenges.