Is chess haram?

I have heard that chess is haram, I would like to know if it is? if its, than why is it haram? I have thought about it's possibilities of why it might be haram, and I came up with that you are wasting your time playing, but than I realized that you are not really wasting time because in learning chess you are learning strategy and that is good to learn. So my questions are, is chess haram? if so than why is it haram?