Ronbun Hakase (論文博士) is a method of obtaining a doctoral degree by way of dissertation without taking or completing a course of study.
[4] Ronbun hakase is rare in comparison with katei hakase which is the primary way of obtaining a doctoral degree[5] as obtaining a ronbun hakase requires the candidate to meet stringent academic background requirements such as having published more peer-reviewed papers than the degree-granting university requires at the time of the application, having published many non-peer-reviewed papers, having experience presenting at international conferences, or having experience as a committee member at an academic society, etc.
[5] Moreover, even if the university's examination determines the candidate is someone with advanced academic ability, they may not receive a ronbun hakase.
[1] On the other hand, some consider it important for promoting the transition to lifelong learning as part of the Ministry of Education, Culture, Sports, Science and Technology policy by conferring doctoral degrees to working individuals who can independantly undertake research, have abunduant knowledge, and are evaluated to have academic ability equivalent or superior to those who have previously received doctoral degrees.
[1] While the proportion of ronbun hakase to katei hakase is decreasing, there are still many who have accumulated considerable experience in a government office or private research organization and cannot undertake a course due to work or personal obligations.