For creating a commercial LENR system- using the Piantelli know-how plus increased energy density- he has applied first Rule No. 5: “NOT what we know, but what we don’t know, is more important for solving the problem.” This means Rossi was aware that the solution is not hidden somewhere in the already published many LENR papers, patents and reports; it is also not in the brain of some great authority from the field. Instead, he has made many probably hundreds, of experiments (here I believe him!) Edisonian style and step-by-step and/or luck-by-luck has found something of value. In the realm of the unknown.
A lengthy post worthy of reading if you have the time.