Implementing lean management systems is based on implementing lean tools and fundamental cultural change. Most organizations manage to apply several lean tools on the technical level but find it hard to make the leap towards true lean transformation. Tidhar, a leading Israeli construction company, was no different. Its journey started with implementing VSM, A3 and parts of the LPS™, but in order to make a significant change a concentrated management training program was necessary. 'Tidhar Lean Boot Camp' is a basic six day lean training program and its purpose is to transform traditional managers into lean managers by breaking existing paradigms, understanding wastes, seeing them first hand in the Gemba and learning to use standard lean management tools to eliminate them. This article reports on the learning achieved during two days of a recent boot camp session that were devoted to first-hand work in the Gemba, where ten experienced managers from different levels and departments undertook trade work in the field. The results were overwhelming as each manager came back with at least two or three fundamental wastes that could not be noticed in any way other than by living this experience.