Mr. Who? Besides one of my childhood heroes, Mr. Miyagi is a fictional karate master from Okinawa, Japan, in the movie series “The Karate Kid”. He was the karate mentor of several people and made them worthy champions. I wanted to be each of those people and then my own karate journey started with my own “sensei" (mentor). Then I became a lawyer and got a so-called “patroon" (another mentor). When I took my first steps in my career switch to the IT world, I discovered that mentorship is not a matter of course. What a pity! Fortunately, I managed to find one again. I have experienced the difference of not having and having one, as a difference between day and night. I would like to talk about the mentorship’s “what”, “who” and “how”. I would also like to tell you about the importance of mentorship in our field and what it could offer us. In doing so, I want to share my own experiences and opinion about this, and also link this to other examples from practice and preferably also to a piece of available (scientific) research. I think that we as a Java and Developers community, but also as an employer and client, should not want anything else and I would like to tell you why.