A 1941 Principia, the first self-wound watch from brothers in independent watchmaking Bart and Tim Grönefeld. This example sports a grained salmon dial in a steel case. Its calibre G-06 features bridges constructed of steel, far harder to shape and finish than brass, with the Dutch bell gable shape and distinctive finishing style that built the Grönefeld brothers name. It is the ultimate in minimalist Dutch watchmaking, in a lovely traditional salmon tone.