Abstract: Because civil-law systems hire unproven jurists into career judiciaries, many maintain elaborate incentive structures to prevent their judges from shirking. We use personnel data (backgrounds, judicial decisions, job postings) on 275 Japanese judges to explore general determinants of career success and to test how extensively politicians manipulate career incentives for political ends. We find strong evidence that the judicial system rewards the smartest and most productive judges. Contrary to some observers, we find no evidence of on-going school cliques, and no evidence that the system favors judges who mediate over those who adjudicate. More controversially, we locate three politically driven phenomena. First, even as late as the 1980's, judges who joined a prominent leftist organization in the 1960's were receiving less attractive jobs. Second, judges who decided a high percentage of cases against the government early in their careers were still receiving less attractive jobs than their peers in the 1980s. Finally, whenever a judge decided a case against the government, he incurred a significant risk that the government would soon punish him with a less attractive post.