Japan occupies a vantage point to observe the intersecting theories of fiduciary law and transnational legal ordering. Having modernized its legal system by introducing western law since the late nineteenth century, Japan possesses a body of law that have been influenced by comparatively diverse sources including both civil law and common law traditions, as well as traditional value system. Japan also has a complex past in the region, initially acting as a colonial power to impose its modernized law onto Korea and Taiwan, then as a leading economy in the post-war years, though the past quarter century has witnessed its struggle. Such diversity and dynamics have affected the evolution of fiduciary norms in Japan and in East Asia, and the main part of this Article will trace the historical progression. In Japan and major East Asian jurisdictions, although the terms “fiduciary” and “duty of loyalty” were not part of the legal lexicon until recent decades, the basic notion of duty of care and the context-specific regulation of conflicted transaction were part of the law. The fiduciary norms evolved as their multiple strands of sources interacted with each other, or even came into conflict with each other. The ever-increasing economic interactions increased the pace and dynamics of this process, and regional and global financial crises added to the sense of urgency. This Article will use the framework of transnational legal ordering to understand the complex evolution of fiduciary norms in Japan, East Asia and beyond.