The young Berlin-based architect Bodo Ebhardt was appointed by Wilhelm II to supervise the project. Both an architect and a specialist in fortresses, he worked according to a strict set of principles.
Firstly, he kept and analyzed the remaining ruins and wall façades. Then he looked up and analyzed many old documents and records. Finally, he examined other European castles and drew comparisons between them and Haut-Koenigsbourg.
All this research enabled him to identify the different parts of the château, to create interior designs of a type that could have featured in the original building and to rebuild the ruin in a way that was historically as accurate as possible.
The parts of the wall that were still standing were checked, stone by stone and the weaker sections were replaced with identically-sized and shaped stones. A coating gave a uniform look to the finished walls. In order to show which parts had been newly restored, B. Ebhardt created a new set of 'mason's marks' - each replacement stone had a special mark carved into it. Different years were given different marks, there being a total of eight different marks used between 1901 and 1908. Even today these marks can be easily identified and can be seen throughout the castle.