Some public organisations struggle to meet the Open Data requirements fully because their data often have sensitive (personal) information, are of low quality, or have interoperability issues in terms of format and semantics. These restrictions quite often hold for justice domain datasets. In order to be transparent, nevertheless, many of such public organisations do share their data in a way that it partially satisfies the open data requirements. These partially opened datasets do not count as Open Data and, therefore, the efforts that organisations put behind these initiatives are not acknowledged adequately and appropriately. To acknowledge such data opening initiatives, we advocate and describe a method to assess the degree of data openness, as a first step for recognising such so-called Semi-Open Data initiatives. We carry out eight case studies, not only to validate the proposed method, but also to show how the method can be deployed in practice.