I first encountered the Nadca 207 specification in 1999. At that time, a large die weighing 400 kg, hardened by our heat treatment plant, cracked in the die casting foundry, and the tool shop wanted to compensate us for the damage caused. We did not believe that the fault was on our side. But then we learned about the Nadca 207 specification, and because we had good contacts, we invited Mr. Corwyn Berger, one of the co-authors of the specification, to a lecture in the Czech Republic. His presentation "Extended tool life on die casting" permanently changed our views and the way we work in the heat treatment shop.