A tenure-track professorship is an attractive station on the career path of early career researchers: it facilitates independent research and teaching at an early stage. After a successful evaluation process, they can be sure to be tenured.
The open-field professorship offers freedom of choice. RUB provides two of these unrestricted professorships to each faculty, in addition to regular professorships. The faculties have thus the chance to offer a tenure option to renowned researchers and outstanding early career researchers who have secured high-quality third-party funding.