In design methodology, the influence of various factors on design processes is studied. In this article the design of the Brabantia corkscrew is presented as a case study in which these factors are analysed. The aim of the analysis is to gain insight into the way Brabantia took these factors into account in the development of its corkscrew. This insight helps us to understand the success of the corkscrew. An important step in the design process was the search for a solution to a problem with a juridical factor: there was a new patent for a competitive corkscrew on the UK market. In an experience-based approach, a new design was developed that avoided infringement of this patent and thus enabled Brabantia to reach a new favourable combination of technological, market, juridical and aesthetic characteristics in its corkscrew design. The way Brabantia originally designed the corkscrew and later changed that design presents an example of what can be called ‘piecemeal rationality’ (this concept is explained in the paper). The article first describes the setting in which the design process took place (Section 1). Then the design methodological focus of the case study is presented (Section 2). Next an analysis of the design process before the patent problem emerged is given in Section 3. The search for a new design was led by a juridical analysis of the patent claims, and this process is described in Section 4. Finally, conclusions are drawn with respect to the question of whether Brabantia's corkscrew design process can be seen as an example of piecemeal rationality (Section 5).